JP2014024361A - Vehicle member including methacryl resin - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a vehicle member including a methacryl resin having high heat resistance, and excellent transparency, moist heat resistance, and molding processability.SOLUTION: A vehicle member includes a methacryl resin that includes a methacrylate ester monomer unit (A):70-95 mass% and a maleimide monomer unit (B):5-30 mass% and has a weight average molecular weight of more than 300,000 to 1,000,000 or less, measured with a gel permeation chromatography (GPC).

Description

  The present invention relates to a vehicle member including a methacrylic resin.

Methacrylic resins represented by polymethyl methacrylate (PMMA) are widely used in the fields of optical materials, automotive parts, building materials, lenses, household goods, OA equipment, lighting equipment, etc. due to their high transparency. ing.
In particular, from the viewpoint of scratch resistance and transparency, many methacrylic resins are used in the field of vehicle members.

In recent years, in particular, instruments mounted on vehicles have been increasingly installed in locations that are easily exposed to direct sunlight from the viewpoint of vehicle interior design, instrument visibility, etc. There is a tendency to lay down.
In view of the above-mentioned circumstances, from the viewpoint of heat resistance, polycarbonate resin may be used as a material for an instrument cover mounted on a vehicle. However, since polycarbonate resin is inferior in scratch resistance, a hard coat is applied to the surface. This has the problem that the shape is limited and the cost is increased.
As a methacrylic resin with improved heat resistance, for example, a resin mainly composed of methyl methacrylate homopolymer has been proposed (see, for example, Patent Document 1).

JP 2001-226429 A

  However, even in the methacrylic resin described in Patent Document 1, the heat resistance required as a material for a vehicle member such as an instrument cover placed under a high temperature condition as described above is still insufficient. High heat resistance is required.

  Therefore, an object of the present invention is to provide a vehicle member containing a methacrylic resin, which is further improved in heat resistance and is excellent in transparency, moist heat resistance and molding processability.

As a result of intensive studies to solve the above-described problems of the prior art, the present inventors have completed the present invention.
That is, the present invention is as follows.

[1]
Methacrylic acid ester monomer unit (A): 70 to 95% by mass,
Maleimide monomer unit (B): 5 to 30% by mass
Containing,
The member for vehicles containing the methacrylic resin whose weight average molecular weight measured by gel permeation chromatography (GPC) exceeds 300,000 and is 1,000,000 or less.
[2]
The vehicle member according to [1], wherein the maleimide monomer (B) is N-cyclohexylmaleimide and / or N-phenylmaleimide.
[3]
[1] including a methacrylic resin further containing another vinyl monomer unit (C) copolymerizable with the methacrylic acid ester monomer unit (A) and the maleimide monomer (B). Or the member for vehicles as described in [2].
[4]
The other vinyl monomer units (C) copolymerizable with (A) and (B) are a group consisting of an aromatic vinyl monomer, an acrylate monomer, and a vinyl cyanide monomer. The vehicle member according to [3], which is at least one kind selected from the above.
[5]
The other vinyl monomer units (C) copolymerizable with (A) and (B) are at least one selected from the group consisting of methyl acrylate, ethyl acrylate, styrene, and acrylonitrile. 3] or the vehicle member according to [4].
[6]
The methacrylic resin is
For a total amount of 100 parts by mass of the methacrylic acid ester monomer unit (A) and the maleimide monomer unit (B),
Containing 0 to 30 parts by mass of other vinyl monomer units (C) copolymerizable with (A) and (B),
The vehicle member according to any one of [3] to [5].
[7]
The vehicle member according to any one of [1] to [6], wherein the thickness is 0.1 to 5 mm.
[8]
The vehicle member according to any one of [1] to [7], wherein the methacrylic resin has a VICAT softening temperature of 117 ° C or higher.
[9]
The vehicle member according to any one of [1] to [8], which is a vehicle instrument cover.

  According to the present invention, it is possible to provide a vehicle member including a methacrylic resin having high heat resistance and excellent transparency, wet heat resistance, and molding processability.

Hereinafter, a mode for carrying out the present invention (hereinafter referred to as “the present embodiment”) will be described in detail. The following embodiments are examples for explaining the present invention, and are not intended to limit the present invention to the following contents. The present invention can be implemented with various modifications within the scope of the gist.
Hereinafter, the structural unit constituting the polymer is referred to as “˜monomer unit”.
Moreover, when describing as a constituent material of methacrylic resin which comprises the member for vehicles of this embodiment, a "unit" may be abbreviate | omitted and may only be described as "... monomer."

[Vehicle parts]
The member for vehicles of this embodiment contains methacrylic acid ester monomer unit (A): 70-95 mass%, maleimide type monomer unit (B): 5-30 mass%, and gel permeation chromatography. It is a member for vehicles containing the methacrylic resin whose weight average molecular weight measured by (GPC) exceeds 300,000 and is 1,000,000 or less.
Hereinafter, the methacrylic resin included in the vehicle member of the present embodiment will be described in detail.

(Methacrylic resin)
The methacrylic resin used for the vehicle member of this embodiment contains a methacrylic acid ester monomer unit (A): 70 to 95% by mass and a maleimide monomer unit (B): 5 to 30% by mass. Further, the methacrylic resin for a vehicle member of the present embodiment can be copolymerized with other copolymerizable monomer units within a range in which the effects of the present invention can be achieved.
Since the methacrylic resin for a vehicle member of the present embodiment is used in a field where heat resistance is required, the VICAT softening temperature is 117 ° C. from the viewpoint of the thermal stability of the vehicle member during constant temperature and humidity. It is preferable that it is above, More preferably, it is 120 degreeC or more. The VICAT softening temperature can be measured according to ISO 306 B50.
By setting the copolymerization ratio of the maleimide monomer unit (B) to the above-described ratio, it is possible to impart high heat resistance while maintaining molding processability and transparency.
The details of each monomer component are described below.

<Methacrylic acid ester monomer unit (A)>
The methacrylic acid ester monomer unit (A) (hereinafter sometimes referred to as (A) component) constituting the methacrylic resin for a vehicle member of the present embodiment is represented by the following general formula (1). The monomers shown are preferably used.

In the general formula (1), R ₁ represents a methyl group. R ₂ represents a group having 1 to 12 carbon atoms, preferably a hydrocarbon group having 1 to 12 carbon atoms, and may have a hydroxyl group on the carbon.

The methacrylic acid ester monomer represented by the general formula (1) is not particularly limited, and examples thereof include butyl methacrylate, ethyl methacrylate, methyl methacrylate, propyl methacrylate, isopropyl methacrylate, and methacrylic acid. Examples include cyclohexyl, phenyl methacrylate, methacrylic acid (2-ethylhexyl), methacrylic acid (t-butylcyclohexyl), benzyl methacrylate, methacrylic acid (2,2,2-trifluoroethyl) and the like. In view of the above, methyl methacrylate is preferable.
The said methacrylic acid ester monomer may be used individually by 1 type, and may use 2 or more types together.

The methacrylic acid ester monomer unit is contained in the methacrylic resin for a vehicle member of this embodiment in an amount of 70 to 95% by mass from the viewpoint of heat resistance imparting effect by the maleimide monomer (B) described later. And preferably 74 to 95% by mass, more preferably 75 to 95% by mass, still more preferably 75 to 93% by mass, and even more preferably 80 to 90% by mass.
The content of the methacrylic acid ester monomer unit (A) can be adjusted by the charged amount of the raw methacrylic acid ester monomer during the polymerization of the methacrylic resin.
The content of the methacrylic acid ester monomer unit (A) can be measured by analyzing a methacrylic resin by a conventionally known method such as an NMR method.

<Maleimide monomer unit (B)>
The maleimide monomer unit (B) constituting the methacrylic resin for vehicle members of the present embodiment (hereinafter sometimes referred to as component (B)) is represented by the following general formula (2). The monomer to be used is preferably used.

R ₃ in the general formula (2) is selected from the group consisting of a hydrogen atom, an alkyl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, and an aryl group having 6 to 12 carbon atoms. Which may have a substituent on the carbon atom.

The monomer constituting the maleimide monomer unit (B) is not particularly limited, and examples thereof include maleimide, N-methylmaleimide, N-ethylmaleimide, N-cyclohexylmaleimide, and N-phenylmaleimide. N- (o-chlorophenyl) maleimide, N- (m-chlorophenyl) maleimide, N- (p-chlorophenyl) maleimide and the like.
Preferred examples include N-cyclohexylmaleimide, N-phenylmaleimide, N- (o-chlorophenyl) maleimide, N- (m-chlorophenyl) maleimide, N- (p-chlorophenyl) maleimi, and availability and heat resistance. From the viewpoint of imparting sex, more preferred are N-cyclohexylmaleimide and N-phenylmaleimide, and more preferred is N-phenylmaleimide.
The maleimide monomer (B) described above may be used alone or in combination of two or more.
The maleimide monomer unit (B) is contained in the methacrylic resin for a vehicle member of the present embodiment from the viewpoint of imparting heat resistance, preferably 5 to 25% by mass. More preferably, it is contained in an amount of 10 to 25% by mass.
The content of the maleimide monomer unit (B) can be adjusted by the charged amount of the raw maleimide monomer during polymerization of the methacrylic resin.
The content of the maleimide monomer unit (B) can be measured by analyzing the methacrylic resin by a conventionally known method such as an NMR method.

<Other vinyl monomer units (C) copolymerizable with (A) and (B)>
In the methacrylic resin for a vehicle member of the present embodiment, other vinyl monomer units (C) copolymerizable with the component (A) and the component (B) as long as the effects of the present invention are not impaired. ) (Hereinafter may be referred to as component (C)).
The content in the case of using other vinyl monomer units (C) copolymerizable with the component (A) and the component (B) is from the viewpoint of exerting the heat resistance imparting effect by the component (B). When the total amount of component (A) and component (B) is 100 parts by mass, it is preferably 30 parts by mass or less, more preferably 25 parts by mass or less, still more preferably 20 parts by mass or less, and even more preferably. Is 18 parts by mass or less.
The content of the other vinyl monomer units (C) can be adjusted by the amount of the vinyl monomer used as a raw material when the methacrylic resin is polymerized.
The content of the other vinyl monomer units (C) can be measured by analyzing the methacrylic resin by a conventionally known method such as an NMR method.

  The monomer constituting the component (C) is not particularly limited. For example, an aromatic vinyl monomer represented by the following general formula (3) or a general formula (4) Acrylic acid ester monomers, vinyl cyanide monomers such as acrylonitrile and methacrylonitrile; amides such as acrylamide and methacrylamide; ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, Ethylene glycol such as triethylene glycol di (meth) acrylate, tetraethylene glycol di (meth) acrylate or the like, and both terminal hydroxyl groups of its oligomer esterified with acrylic acid or methacrylic acid; neopentyl glycol di (meth) acrylate, di Hydroxyl group of two alcohols such as (meth) acrylate Those that have been esterified with acrylic acid or methacrylic acid; trimethylolpropane, those polyhydric alcohol derivatives such as pentaerythritol was esterified with acrylic acid or methacrylic acid; polyfunctional monomers such as divinylbenzene, and the like.

In the general formula (3), R ₄ represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, and may have a hydroxyl group on the alkyl group.
n represents an integer of 0 to 5.
R ₅ is a group consisting of a hydrogen atom, an alkyl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, an aryl group having 1 to 8 carbon atoms, and an aryl group having 1 to 8 carbon atoms. Any of R ₅ may be selected, and all R ₅ may be the same group or different groups.
Further, R ₅ may form a ring structure.

In the general formula (4), R ₆ is a hydrogen atom, and R ₇ is an alkyl group having 1 to 18 carbon atoms.

  As the monomer constituting the component (C), it can be used as appropriate according to the characteristics required of the vehicle member, but the characteristics such as thermal stability, fluidity, mechanical characteristics, and chemical resistance are particularly good. If necessary, it is preferable to suitably select and suitably use at least one selected from the group consisting of aromatic vinyl monomers, acrylate monomers, and vinyl cyanide monomers.

[Aromatic vinyl monomer units (C-1)]
The monomer constituting the aromatic vinyl monomer unit is not particularly limited, and examples thereof include styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, 2,4- Dimethylstyrene, 2,5-dimethylstyrene, 3,4-dimethylstyrene, 3,5-dimethylstyrene, p-ethylstyrene, m-ethylstyrene, о-ethylstyrene, p-tert-butylstyrene, 1-vinylnaphthalene , 2-vinylnaphthalene, 1,1-diphenylethylene, isopropenyl benzene (α-methylstyrene), isopropenyl toluene, isopropenyl ethyl benzene, isopropenyl propyl benzene, isopropenyl butyl benzene, isopropenyl pentyl benzene, isopropenyl hexyl benzene , Isopropenyl Examples include octylbenzene.
These are appropriately selected according to required characteristics in the methacrylic resin for a vehicle member of the present embodiment. Among these, styrene and isopropenylbenzene are preferable, and styrene is more preferable from the viewpoints of imparting fluidity and reducing unreacted monomers by improving the polymerization conversion rate.
When using the aromatic vinyl monomer unit (C-1), the blending ratio (mass ratio) of the aromatic vinyl monomer unit (C-1) and the maleimide monomer unit (B). From the viewpoint of processing fluidity at the time of molding a member for a vehicle, an effect of reducing silver streak by reducing residual monomers, it is preferable to satisfy the following formula.
0.3 ≦ (C-1) / (B) ≦ 5
From the viewpoint of maintaining good color tone and heat resistance, the upper limit value is preferably 5 or less, more preferably 3 or less, and even more preferably 1 or less.
Moreover, it is preferable that it is 0.3 or more from a viewpoint of residual monomer reduction, More preferably, it is 0.4 or more.
The aromatic vinyl monomer units (C-1) described above may be used alone or in combination of two or more.

[Acrylic acid ester monomer units (C-2)]
As the monomer constituting the acrylate monomer unit (C-2), as described above, in the general formula (4), the substituent R ₇ is an alkyl group having 1 to 18 carbon atoms. In particular, in the methacrylic resin for a vehicle member of the present embodiment, methyl acrylate, ethyl acrylate, n-acrylic acid are used from the viewpoint of improving weather resistance, heat resistance, fluidity, and thermal stability. -Propyl, n-butyl acrylate, sec-butyl acrylate, 2-ethylhexyl acrylate and the like are preferable, and methyl acrylate, ethyl acrylate and n-butyl acrylate are more preferable. From the viewpoint, methyl acrylate is more preferable.
In the case of using the acrylate monomer unit (C-2), the total amount of the component (A) and the component (B) is 100 parts by mass from the viewpoints of heat resistance and thermal stability. In this case, the amount is preferably 5 parts by mass or less, more preferably 3 parts by mass or less.
As for the acrylate monomer unit (C-2), only one type may be used alone, or two or more types may be used in combination.

[Vinyl cyanide monomer unit (C-3)]
The monomer constituting the vinyl cyanide monomer unit (C-3) is not particularly limited, and examples thereof include acrylonitrile, methacrylonitrile, vinylidene cyanide, and acrylonitrile is preferably used. Is done.
In the case of using the vinyl cyanide monomer unit (C-3), the total amount of the component (A) and the component (B) is 100 parts by mass from the viewpoint of solvent resistance and heat resistance. When it is, it is preferable that it is 15 mass parts or less, More preferably, it is 12 mass parts or less, More preferably, it is 10 mass parts or less.

  As other vinyl monomers (C) copolymerizable with the above (A) and (B), the effects of imparting thermal stability, fluidity, mechanical properties, chemical resistance, etc., and easy availability Therefore, at least one selected from the group consisting of methyl acrylate, ethyl acrylate, styrene, and acrylonitrile is preferable.

(Molecular weight of methacrylic resin)
The methacrylic resin for a vehicle member of the present embodiment has a weight average molecular weight of more than 300,000 and 1,000,000 or less. By setting the weight average molecular weight within the above range, a methacrylic resin and a vehicle member excellent in mechanical strength and solvent resistance can be obtained. Preferably they are 350,000 or more and 1 million or less, More preferably, they are 350,000 or more and 800,000 or less.
The molecular weight distribution (weight average molecular weight / number average molecular weight: Mw / Mn) is preferably 1.5 or more and 5 or less from the viewpoint of the balance between fluidity, mechanical strength, and solvent resistance. More preferably, it is 1.5 or more and 4.5 or less, More preferably, it is 1.6 or more and 3 or less, More preferably, it is 1.6 or more and 2.5 or less.
The weight average molecular weight, number average molecular weight, and peak molecular weight of the methacrylic resin for vehicle members of this embodiment are measured by gel permeation chromatography (GPC).
That is, using a standard methacrylic resin, which is known in advance and has a monodispersed weight average molecular weight, number average molecular weight, and peak molecular weight, and an analytical gel column that elutes a high molecular weight component first, elution time and weight average molecular weight Create a calibration curve from Next, from the obtained calibration curve, the weight average molecular weight, number average molecular weight, and peak molecular weight of the sample of the methacrylic resin to be measured can be obtained.
Specifically, it can measure by the method as described in the Example mentioned later.

(Method for producing methacrylic resin)
Hereinafter, although the manufacturing method of the methacrylic resin for members for vehicles of this embodiment is explained, it is not limited to the method shown below.
The methacrylic resin includes a methacrylic acid ester monomer (A), a maleimide monomer (B), and other vinyl monomers copolymerizable with the above-described (A) and (B) as necessary. Using (C), it can be produced by a bulk polymerization method, a solution polymerization method, a suspension polymerization method, a precipitation polymerization method, or an emulsion polymerization method. A bulk polymerization method, a solution polymerization method, and a suspension polymerization method are preferably used, a solution polymerization method and a suspension polymerization method are more preferable, and a suspension polymerization method is more preferably used.

<Production method by solution polymerization method>
In the case of producing a methacrylic resin by a solution polymerization method, it is preferable to use an organic solvent that is a good solvent for the methacrylic resin in consideration of the removal efficiency in the step of removing the monomer remaining in the methacrylic resin.
Considering the solubility of the copolymer constituting the methacrylic resin, the solubility parameter δ of the organic solvent is preferably 7.0 to 12.0 (cal / cm ³ ) ^1/2 , more preferably It is 8.0-11.0, More preferably, it is 8.2-10.5.
The value of the solubility parameter δ and how to obtain the value are described in, for example, K. P. P-P118 in Non-Patent Document “Journal of Paint Technology Vol. 42, No. 541, February 1970”. L. Hoy “New Values of the Solubility Parameters From Vapor Pressure Data” For example, Brandrup et al., “Polymer Handbook Fourth Edition” P-VII / 675-P714 can be referred to.
1 (cal / cm ³ ) ^1/2 is about 0.489 (MPa) ^1/2 .

The addition amount of the organic solvent used in the polymerization step of the copolymer constituting the methacrylic resin for vehicle members of the present embodiment is such that the polymerization proceeds and no precipitation of the copolymer or used monomers occurs during production. The amount must be easily removable.
When the solution polymerization method is used, the amount of the organic solvent is preferably 25 parts by mass or more and 200 parts by mass or less when the total amount of the monomers to be blended is 100 parts by mass. More preferably, they are 50 to 200 mass parts, More preferably, they are 75 to 200 mass parts, More preferably, they are 75 to 150 mass parts.

When performing a polymerization reaction continuously, the organic solvent and monomer collect | recovered from a reaction system may be recycled and used. Usually, the organic solvent and the monomer are volatilized from the polymerization solution by heating, and the organic solvent and the monomer are recovered by further cooling.
When cooling, it is carried out at a low temperature of 0 ° C. or lower, and in some cases −10 ° C. or lower. However, when the amount of the organic solvent used is less than 25 parts by mass when the total amount of the blended monomers is 100 parts by mass, There is a possibility that unreacted monomers are precipitated. When the amount exceeds 200 parts by mass, the amount of polymer obtained is small, and thus productivity is lowered.

The polymerization temperature in the case of producing a methacrylic resin by solution polymerization is not particularly limited as long as the polymerization proceeds, but is preferably 50 ° C. or more and 200 ° C. or less from the viewpoint of productivity. Preferably they are 90 degreeC or more and 200 degrees C or less. More preferably, they are 100 degreeC or more and 200 degrees C or less, More preferably, they are 100 degreeC or more and 180 degrees C or less, More preferably, they are 110 degreeC or more and 170 degrees C or less, Especially preferably, they are 120 degreeC or more and 160 degrees C.
The polymerization time is not particularly limited as long as the required degree of polymerization can be obtained, but it is preferably 0.5 hours or more and 6 hours or less, more preferably from the viewpoint of productivity and the like. Is from 1 hour to 5 hours, more preferably from 1 hour to 3 hours.

  In the polymerization step of the methacrylic resin, the dissolved oxygen concentration in the polymerization solution is preferably 10 ppm or less. The dissolved oxygen concentration can be measured using, for example, a dissolved oxygen meter DO meter B-505 (manufactured by Iijima Electronics Co., Ltd.). The method for reducing the dissolved oxygen concentration to 10 ppm or less is not particularly limited. For example, a method of bubbling an inert gas in the polymerization solution, or an inert gas in the container containing the polymerization solution before the polymerization. Methods such as a method of repeating the operation of releasing after pressurizing to about 0.2 MPa, a method of passing an inert gas in a container containing a polymerization solution, and the like can be appropriately selected.

<Production method by suspension polymerization method>
When the copolymer constituting the methacrylic resin for a vehicle member of the present embodiment was produced by suspension polymerization such as organic suspension polymerization method or inorganic suspension polymerization method, a stirrer described later was used. A particulate methacrylic resin is produced through a polymerization step, a washing step, a dehydration step, and a drying step. Usually, an aqueous suspension polymerization method using water as a medium is preferably used.

<Polymerization process>
Using a stirrer to be described later, a monomer, a suspending agent, and a polymerization initiator and other additives as necessary are appropriately fed into the stirrer to perform polymerization, and a methacrylic resin slurry is prepared. obtain.
The stirrer used in the polymerization step for obtaining a methacrylic resin by suspension polymerization is not particularly limited. For example, an inclined paddle blade, a flat paddle blade, a propeller blade, an anchor blade, and a fiddler are used. Stirring devices with stirring blades such as blades (retracted blades), turbine blades, bull margin blades, max blend blades, full zone blades, ribbon blades, supermix blades, intermig blades, special blades and axial flow blades, shovel blades inside Well-known stirring devices such as a stirring device having a chopper blade inside, a stirring device having a rotating disk such as a disk type, a notch disk type or a screw type inside.
The stirring speed at the time of polymerization depends on the type of stirring device used, the stirring efficiency of the stirring blade, the capacity of the polymerization tank, etc., but it is possible to obtain an appropriate particle size, and a component having a particle size of less than 0.15 mm Considering that the amount can be reduced and that the polymerization stability is obtained, it is preferably about 1 to 500 revolutions / minute.

The temperature at which the raw material mixture of the methacrylic resin is added may be within a range in which the effect of the present invention can be exerted, and is preferably 0 ° C. or higher and lower than the boiling point of the raw material to be used.
If the temperature is high, the raw material tends to volatilize at the time of addition, so the composition of the monomer units constituting the methacrylic resin changes, and if the temperature is lower than 0 ° C, it takes time to increase the temperature after adding the raw material. Therefore, it is preferable to add the raw material mixture at a certain temperature. Specifically, it is preferably 0 ° C. or higher and 85 ° C. or lower, more preferably 10 ° C. or higher and 85 ° C. or lower, more preferably 30 ° C. or higher and 85 ° C. or lower, and even more preferably 50 ° C. or higher and 80 ° C. or lower. More preferably, it is 60 ° C. or more and 80 ° C. or less.

The temperature in the suspension polymerization step is preferably 40 ° C. or higher and 90 ° C. or lower in consideration of productivity and the amount of aggregates produced. More preferably, it is 50 degreeC or more and 85 degrees C or less, More preferably, it is 60 degreeC or more and 85 degrees C or less, More preferably, it is 65 degreeC or more and 83 degrees C or less.
In the case of producing by suspension polymerization, the polymerization time is preferably 20 minutes or more and 240 minutes or less from the viewpoint of effectively suppressing heat generation during polymerization and reducing the generation of aggregates to be described later and the reduction of residual monomer. is there. More preferably, they are 30 minutes or more and 210 minutes or less, More preferably, they are 45 minutes or more and 180 minutes or less, More preferably, they are 60 minutes or more and 180 minutes or less, More preferably, they are 90 minutes or more and 150 minutes or less.

Further, from the viewpoint of reducing the residual monomer, it is preferable to raise the temperature to a temperature higher than the polymerization temperature after the polymerization step and hold it for a certain time. The temperature at the time of holding is preferably higher than the polymerization temperature from the viewpoint of increasing the degree of polymerization, and when higher, it is preferable to raise the temperature by 5 ° C. or more from the polymerization temperature. When raising temperature, it is preferable that it is below the glass transition temperature of the methacrylic resin obtained from a viewpoint of preventing aggregation of the polymer obtained. Specifically, it is preferably 120 ° C. or lower, more preferably 100 ° C. or lower, further preferably 80 ° C. or higher and 100 ° C. or lower, still more preferably 85 ° C. or higher and 100 ° C. or lower, and still more preferably 88 ° C. or higher and 100 ° C. or lower. Hereinafter, it is particularly preferably 90 ° C or higher and 100 ° C or lower.
By performing the polymerization in accordance with the polymerization temperature and holding time described above, polymer particles having a small angle of repose can be generated after the drying step described later.
The time for maintaining the temperature after the temperature rise is preferably 15 minutes or more and 360 minutes or less, more preferably 30 minutes or more and 240 minutes or less, more preferably 30 minutes or more and 180 minutes, in view of the effect of reducing the residual monomer. Hereinafter, it is more preferably 30 minutes or longer and 150 minutes or shorter, and even more preferably 30 minutes or longer and 120 minutes or shorter.

<Washing process>
The methacrylic resin slurry obtained through the above polymerization step is preferably subjected to operations such as acid washing, water washing, and alkali washing in order to remove the suspending agent.
What is necessary is just to select the optimal frequency | count from the work efficiency and the removal efficiency of a suspension agent as the frequency | count of performing these washing | cleaning operation, and you may repeat once or several times.
What is necessary is just to select the temperature at the time of washing | cleaning in consideration of the removal efficiency of a suspension agent, the coloring degree of the obtained methacrylic resin, etc., and it is preferable that it is 20-100 degreeC. More preferably, it is 30-95 degreeC, More preferably, it is 40-95 degreeC.
The washing time per washing is preferably 10 to 180 minutes, more preferably 20 to 150 minutes from the viewpoints of washing efficiency, a repose angle reduction effect of polymer particles, and process simplicity. .
The pH of the cleaning solution used at the time of the cleaning may be within a range where the suspension can be removed, but is preferably pH 1-12. The pH for acid washing is preferably pH 1-5, more preferably pH 1.2-4, from the viewpoint of the removal efficiency of the suspending agent and the color tone of the resulting copolymer. The acid used at that time is not particularly limited as long as the suspending agent can be removed, and conventionally known inorganic acids and organic acids can be used. As an example of the acid that is preferably used, the inorganic acid includes hydrochloric acid, nitric acid, sulfuric acid, phosphoric acid, boric acid and the like, and each may be used in a diluted solution diluted with water or the like. Examples of the organic acid include those having a carboxyl group, a sulfo group, a hydroxy group, a thiol group, or an enol. Considering the effect of removing the suspending agent and the color tone of the resulting resin, more preferred are nitric acid, sulfuric acid, and organic acids having a carboxyl group.
After the acid washing, it is preferable to perform further washing with water and alkali washing from the viewpoint of the color tone of the resulting methacrylic resin and the angle of repose of the polymer particles.
The pH of the alkaline solution when performing alkali cleaning is preferably pH 7.1 to 12, more preferably pH 7.5 to 11, and still more preferably 7.5 to 10.5.
As the alkaline component used for alkali cleaning, tetraalkylammonium hydroxide, alkali metal hydroxide, alkaline earth metal hydroxide and the like are preferably used. Alkali metal hydroxides and alkaline earth metal hydroxides are more preferable, and lithium hydroxide, sodium hydroxide, potassium hydroxide, rubidium hydroxide, cesium hydroxide, magnesium hydroxide, hydroxide are more preferable. Calcium and barium hydroxide are more preferable, lithium hydroxide, sodium hydroxide, potassium hydroxide, magnesium hydroxide and calcium hydroxide are more preferable, and sodium hydroxide and potassium hydroxide are still more preferable.
These alkaline components can be used by adjusting the pH by diluting with water or the like.

<Dehydration process>
As a method for separating the polymer particles from the polymer slurry of the obtained methacrylic resin, a conventionally known method can be applied.
For example, a dehydration method using a centrifuge that shakes off water using centrifugal force, a method of separating water by sucking and removing water on a porous belt or a filtration membrane, and the like can be mentioned.

<Drying process>
The water-containing polymer obtained through the above-described dehydration step can be recovered by performing a drying treatment by a known method.
For example, hot air drying for drying by sending hot air into the tank from a hot air blower or blow heater, etc., vacuum drying for drying by heating as necessary after reducing the pressure inside the system, and obtained polymer For example, barrel drying for removing moisture by rotating the container in a container, spin drying for drying using centrifugal force, and the like. These methods may be used alone or in combination.
The water content of the obtained methacrylic resin is preferably 0.01% by mass to 1% by mass, more preferably 0.05% by mass to 1% by mass, and still more preferably from the viewpoints of handleability, color tone, and the like. Is 0.1% by mass to 1% by mass, and more preferably 0.27% by mass to 1% by mass. The water content of the resulting methacrylic resin can be measured using the Karl Fischer method.

When a methacrylic resin is produced using the suspension polymerization method described above, the resulting methacrylic resin is usually substantially spherical, but some aggregates may be formed.
The aggregate refers to a residue remaining on the sieve when the obtained polymer is passed through a 1.68 mm mesh sieve.
When the aggregate remains in the methacrylic resin, the color tone of the obtained methacrylic resin tends to decrease. The amount of aggregates in the methacrylic resin is preferably 1.2% by mass or less, and more preferably 1.0% by mass or less.
The agglomerate content was passed through a 1.68 mm mesh sieve, and the weight of what was left on the sieve was dried in a drying oven at 80 ° C. for 12 hours, and the obtained weight was the total amount of raw materials. The aggregate production amount (mass%) can be calculated by dividing the above.

The average particle diameter of the methacrylic resin obtained using the suspension polymerization method described above is preferably 0.1 mm or more in consideration of workability during molding and extrusion, etc., and a molded piece obtained by molding In consideration of the color tone, it is more preferably 0.1 mm or more and 1 mm or less, further preferably 0.1 mm or more and 0.5 mm or less, and still more preferably 0.1 mm or more and 0.4 mm or less.
The average particle diameter of the methacrylic resin is, for example, based on JIS-Z8801, sieves (JTS-200-45-44 (aperture 500 μm), 34 (aperture 425 μm), 35 (aperture 355 μm) manufactured by Tokyo Screen), 36 (Aperture 300 μm), 37 (aperture 250 μm), 38 (aperture 150 μm), 61 (a saucer)) was screened for 10 minutes with vibration force MAX using a tester TSK B-1. It is possible to measure by measuring the particle weight remaining on each sieve and determining the particle diameter when the weight is 50%.

<Polymerization initiator>
In various polymerization methods for producing the methacrylic resin contained in the vehicle member of the present embodiment, that is, in the polymerization step in the bulk polymerization method, the solution polymerization method, the suspension polymerization method, and the emulsion polymerization method, the polymer to be produced is polymerized. For the purpose of adjusting the degree, a polymerization initiator may be used.
The polymerization initiator is not particularly limited when radical polymerization is performed, and examples thereof include di-t-butyl peroxide, lauroyl peroxide, stearyl peroxide, benzoyl peroxide, and t-butyl peroxyneo. Decanate, t-butylperoxypivalate, dilauroyl peroxide, dicumyl peroxide, t-butylperoxy-2-ethylhexanoate, 1,1-bis (t-butylperoxy) -3,3 Organic peroxides such as 1,5-trimethylcyclohexane, 1,1-bis (t-butylperoxy) cyclohexane, azobisisobutyronitrile, azobisisovaleronitrile, 1,1-azobis (1-cyclohexanecarbo Nitrile) 2,2'-azobis-4-methoxy-2,4-azobisui Butyronitrile, 2,2'-azobis-2,4-dimethylvaleronitrile, mention may be made of conventional radical polymerization initiator azo such as 2,2'-azobis-2-methylbutyronitrile.
These may be used alone or in combination of two or more.
A combination of these radical polymerization initiators and an appropriate reducing agent may be used as a redox initiator.
These polymerization initiators are preferably used in the range of 0 to 1 part by mass with respect to 100 parts by mass of the total amount of all monomers used in the polymerization of the methacrylic resin, and the polymerization temperature and initiator. Can be selected as appropriate in consideration of the half-life.
When a bulk polymerization method, a cast polymerization method, or a suspension polymerization method is selected as the polymerization method of the methacrylic resin, from the viewpoint of preventing coloring of the methacrylic resin, the polymerization initiator is lauroyl parper. Oxide, decanoyl peroxide, t-butylperoxy-2-ethylhexanoate and the like can be particularly preferably used, and lauroyl peroxide is particularly preferably used.
Further, as a polymerization method of methacrylic resin, when performing a solution polymerization method at a high temperature of 90 ° C. or higher, a peroxide having a 10-hour half-life temperature of 80 ° C. or higher and soluble in an organic solvent to be used, An azobis initiator or the like is preferable. Specifically, 1,1-bis (t-butylperoxy) -3,3,5-trimethylcyclohexane, cyclohexane peroxide, 2,5-dimethyl-2,5-di (benzoylperoxy) hexane, , 1-azobis (1-cyclohexanecarbonitrile), 2- (carbamoylazo) isobutyronitrile and the like.

<Molecular weight control>
In the production process of the methacrylic resin contained in the vehicle member of the present embodiment, the molecular weight of the polymer to be produced can be controlled within a range that does not impair the object of the present invention.
For example, the molecular weight can be controlled by using chain transfer agents such as alkyl mercaptans, dimethylacetamide, dimethylformamide, triethylamine, etc., dithiocarbamates, triphenylmethylazobenzene, iniferters such as tetraphenylethane derivatives, etc. It is possible to adjust the molecular weight by adjusting the amount of these added.
When these additives are used, alkyl mercaptans are preferably used from the viewpoints of handleability and stability, and are not particularly limited. For example, n-butyl mercaptan, n-octyl mercaptan, n-dodecyl mercaptan , T-dodecyl mercaptan, n-tetradecyl mercaptan, n-octadecyl mercaptan, 2-ethylhexyl thioglycolate, ethylene glycol dithioglycolate, trimethylolpropane tris (thioglycolate), pentaerythritol tetrakis (thioglycolate), etc. .
These can be appropriately added according to the desired molecular weight of the methacrylic resin, but generally in the range of 0.001 to 3 parts by mass with respect to 100 parts by mass of the total amount of all monomers used. Used in
Other molecular weight control methods include a method of changing the polymerization method, a method of adjusting the amount of the polymerization initiator, and a method of changing the polymerization temperature.
As these molecular weight control methods, only one type of method may be used alone, or two or more types may be used in combination.

(Methacrylic resin composition)
The member for vehicles of this embodiment can also be produced using the above-mentioned methacrylic resin and the methacrylic resin composition combined with predetermined other resin mentioned below and a predetermined additive.

<Other resins>
The other resin that can be combined with the methacrylic resin is not particularly limited as long as it can exhibit the characteristics required for the vehicle member, and a known thermoplastic resin can be used.
For example, polypropylene resin, polyethylene resin, polystyrene resin, syndiotactic polystyrene resin, ABS (acrylonitrile-butadiene-styrene) resin, methacrylic resin, AS (acrylonitrile-styrene) resin, BAAS (butyl acrylate- Acrylonitrile-styrene) resin, MBS (methyl methacrylate-butadiene-styrene) resin, AAS (acrylonitrile-acrylic rubber-styrene) resin, biodegradable resin, polycarbonate-ABS resin alloy, polybutylene terephthalate, polyethylene terephthalate, polypropylene terephthalate , Polytrimethylene terephthalate, polyethylene naphthalate and other polyalkylene arylate resins; polyamide resins, polyphenylene Ether-based resins, polyphenylene sulfide resins, phenol resins and the like.
In particular, AS resin and BAAS resin are preferable for improving fluidity, ABS resin and MBS resin are preferable for improving impact resistance, and polyester resin is preferable for improving chemical resistance.
In addition, polyphenylene ether resins, polyphenylene sulfide resins, phenol resins, and the like can be expected to have an effect of improving flame retardancy.
These resins may be used alone or in combination of two or more.

<Additives>
A predetermined additive may be added to the methacrylic resin used for the vehicle member of the present embodiment in order to impart various characteristics such as rigidity and dimensional stability.
The additive is not particularly limited. For example, various stabilizers such as antioxidants, ultraviolet absorbers, heat stabilizers, light stabilizers; plasticizers (paraffinic process oil, naphthenic process oil, Aromatic process oil, paraffin, organic polysiloxane, mineral oil), flame retardant (for example, phosphorus compounds such as organic phosphorus compounds, red phosphorus, inorganic phosphate, halogen-based, silica-based, silicone-based), difficult Fuel aids (for example, antimony oxides, metal oxides, metal hydroxides, etc.), curing agents (diethylenetriamine, triethylenetetramine, tetraethylenepentamine, pentaethylenehexamine, diethylaminopropylamine, 3,9-bis (3 -Aminopropyl) -2,4,8,10-tetraoxaspiro [5,5] undecane, mensendiamine Amphores such as isophoronediamine, N-aminoethylpiperazine, m-xylenediamine, m-phenylenediamine, diaminophenylmethane, diaminodiphenylsulfone, dicyandiamide, adipic acid dihydrazide, and phenolic resins such as phenol novolac resin and cresol novolac resin Polymer captans such as liquid polymercaptan and polysulfide; phthalic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, methyltetrahydrophthalic anhydride, methylhexahydrophthalic anhydride, methylnadic anhydride, pyromellitic anhydride, methyl Cyclohexene tetracarboxylic anhydride, dodecyl succinic anhydride, trimellitic anhydride, chlorendic anhydride, benzophenone tetracarboxylic anhydride, ethylene glycol Acid anhydrides such as coal bis (anhydrotrimate)), curing accelerators (2-methylimidazole, 2-ethylimidazole, 2-ethyl-4-methylimidazole, 2-phenylimidazole, 2-undecylimidazole, 2 -Imidazoles such as heptadecylimidazole and 2-phenyl-4-methylimidazole; Organic phosphines such as triphenylphosphine and tributylphosphine; benzyldimethylamine, 2-dimethylaminomethyl) phenol, 2,4,6-tris ( Tertiary amines such as diaminomethyl) phenol and tetramethylhexanediamine; boron salts such as triphenylphosphine tetraphenylborate, tetraphenylphosphonium tetraphenylborate and triethylaminetetraphenylborate; 1,4 Benzoquinone, 1,4-naphthoquinone, 2,3-dimethyl-1,4-benzoquinone, 2,6-dimethylbenzoquinone, quinoid compounds such as 2,3-dimethoxy-1,4-benzoquinone, etc.), antistatic agents (for example, , Polyamide elastomer, quaternary ammonium salt system, pyridine derivative, aliphatic sulfonate, aromatic sulfonate, aromatic sulfonate copolymer, sulfate ester salt, polyhydric alcohol partial ester, alkyldiethanolamine, alkyldiethanolamide , Polyalkylene glycol derivatives, betaines, imidazoline derivatives, etc.), conductivity imparting agents, stress relieving agents, mold release agents (alcohols, esters of alcohols and fatty acids, alcohols and esters of dicarboxylic acids, silicone oils, etc.), Crystallization accelerator, hydrolysis inhibitor, lubrication (For example, higher fatty acids such as stearic acid, behenic acid, zinc stearate, calcium stearate, magnesium stearate, and metal salts thereof, higher fatty acid amides such as ethylene bisstearamide, etc.), impact imparting agent, slidability Improving agent (hydrocarbon such as low molecular weight polyethylene, higher alcohol, polyhydric alcohol, polyglycol, polyglycerol, higher fatty acid, higher fatty acid metal salt, fatty acid amide, ester of fatty acid and aliphatic alcohol, fatty acid and polyhydric alcohol Full ester or partial ester, fatty acid and polyglycol full ester or partial ester, silicone type, fluororesin type, etc.), compatibilizer, nucleating agent, reinforcing agent, flow control agent, dye (nitroso dye, nitro dye) , Azo dye, Stilbene azo dye, Ketoimine dye, Tripheny Lumethane dye, xanthene dye, acridine dye, quinoline dye, methine / polymethine dye, thiazole dye, indamine / indophenol dye, azine dye, oxazine dye, thiazine dye, sulfur dye, aminoketone / oxyketone dye, anthraquinone dye, indigoid dye, phthalocyanine Dyes such as dyes), sensitizers, colorants (titanium oxide, carbon black, titanium yellow, iron oxide pigments, ultramarine, cobalt blue, chromium oxide, spinel green, lead chromate pigments, cadmium pigments, etc. Pigments, azo lake pigments, benzimidazolone pigments, diarylide pigments, azo pigments such as condensed azo pigments, phthalocyanine pigments such as phthalicyanine blue and phthalocyanine green, isoindolinone pigments, quinophthalone pigments and quinaclides Pigment, perylene pigment, anthraquinone pigment, perinone pigment, organic pigments such as condensed polycyclic pigments such as dioxazine violet, scaly aluminum metallic pigments, spherical aluminum used to improve weld appearance Pigments, mica powder for pearl-like metallic pigments, other metallic pigments such as glass coated inorganic polyhedral particles such as metal plating and sputtering, etc.), thickeners, anti-settling agents, anti-sagging agents, fillers ( Glass fiber, carbon fiber and other fibrous reinforcing agents, glass beads, calcium carbonate, talc, clay, etc.), antifoaming agents (silicone-based antifoaming agents, surfactants, polyethers, higher alcohols, etc.) Foaming agents, etc.), coupling agents, light diffusing fine particles, antirust agents, antibacterial / antifungal agents, antifouling agents, conductive polymers, and the like.

The light diffusing fine particles are not particularly limited. For example, inorganic fine particles such as alumina, titanium oxide, calcium carbonate, barium sulfate, silicon dioxide, and glass beads, styrene cross-linked beads, MS cross-linked beads, and siloxane series. Examples thereof include organic fine particles such as crosslinked beads.
Further, hollow crosslinked fine particles made of a highly transparent resin material such as acrylic resin, polycarbonate resin, MS resin, and cyclic olefin resin, hollow fine particles made of glass, and the like are also included.
In the inorganic fine particles, alumina, titanium oxide and the like are more preferable.
The light diffusing fine particles may be used alone or in combination, and is not limited at all.
Here, the refractive index of the light diffusing fine particles is preferably 1.7 to 3.0, more preferably 1.7 to 2.5, and still more preferably 1.7 to 2.0. If the refractive index is less than 1.7, the scattering property becomes too weak. On the other hand, if it exceeds 3.0, the scattering in the vicinity of the lamp becomes too strong, and as a result, uneven brightness and unevenness in emitted light color tone are likely to occur. Absent.
The refractive index is a value at a temperature of 20 ° C. based on the D line (589 nm). As a method for measuring the refractive index of the fine particles, for example, the fine particles are immersed in a liquid whose refractive index can be changed little by little, and the fine particle interface is observed while changing the refractive index of the liquid. The method of measuring the refractive index of the liquid at the time is mentioned. An Abbe refractometer or the like can be used to measure the refractive index of the liquid.
The average particle diameter of the light diffusing fine particles is preferably 0.1 to 20 μm, more preferably 0.2 to 15 μm, still more preferably 0.3 to 10 μm, and still more preferably 0.4 to 5 μm. An average particle diameter of 20 μm or less is preferable because light loss due to back reflection or the like is suppressed and incident light can be efficiently diffused to the light emitting surface side. In addition, it is preferable that the average particle diameter is 0.1 μm or more because emitted light can be diffused and desired surface emission luminance and diffusibility can be obtained.
Further, the content of the light diffusing fine particles in the methacrylic resin composition is 0.0001 to 0.03 mass with respect to 100 parts by mass of the methacrylic resin from the viewpoint of the expression of the light diffusing effect and the uniformity of surface emission. Parts, preferably 0.0001 to 0.01 parts by weight.

Although it does not specifically limit as said heat stabilizer, For example, antioxidants, such as a hindered phenolic antioxidant and a phosphorus processing stabilizer, are mentioned, A hindered phenolic antioxidant is preferable.
Specifically, pentaerythritol tetrakis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate], thiodiethylenebis [3- (3,5-di-tert-butyl-4-hydroxy) Phenyl) propionate], octadecyl-3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate, 3,3 ′, 3 ″, 5,5 ′, 5 ″ -hexa-tert-butyl -A, a ', a''-(mesitylene-2,4,6-triyl) tri-p-cresol, 4,6-bis (octylthiomethyl) -o-cresol, 4,6-bis (dodecylthio) Methyl) -o-cresol, ethylenebis (oxyethylene) bis [3- (5-tert-butyl-4-hydroxy-m-tolyl) propionate], hexamethylenebis [3- (3,5-di-tert- Butyl-4 -Hydroxyphenyl) propionate], 1,3,5-tris (3,5-di-tert-butyl-4-hydroxybenzyl) -1,3,5-triazine-2,4,6 (1H, 3H, 5H ) -Trione, 1,3,5-tris [(4-tert-butyl-3-hydroxy-2,6-xylin) methyl] -1,3,5-triazine-2,4,6 (1H, 3H, 5H) -trione, 2,6-di-tert-butyl-4- (4,6-bis (octylthio) -1,3,5-triazin-2-ylamine) phenol, and the like. In particular, pentaerythritol terakis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate] is preferable.
A commercially available phenolic antioxidant may be used as the hindered phenolic antioxidant, and such a commercially available phenolic antioxidant is not particularly limited. For example, Irganox 1010 (Irganox 1010: pentaerythritol tetrakis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate], manufactured by Ciba Specialty Chemicals), Irganox 1076 (Irganox 1076: octadecyl-3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate, manufactured by Ciba Specialty Chemicals), Irganox 1330 (Irganox 1330: 3, 3 ′, 3 ″, 5, 5 ′, 5 ′) '-Hexa-t-butyl-a, a', a ''-(mesitylene-2,4 , 6-triyl) tri-p-cresol, manufactured by Ciba Specialty Chemicals), Irganox 3114 (Irganox 3114: 1,3,5-tris (3,5-di-t-butyl-4-hydroxybenzyl) -1,3,5-triazine-2,4,6 (1H, 3H, 5H) -trione, manufactured by Ciba Specialty Chemicals), Irganox 3125 (Irganox 3125, manufactured by Ciba Specialty Chemicals) BHT (Sumilizer BHT, manufactured by Sumitomo Chemical), Cyanox 1790 (Cyanox 1790, manufactured by Cytec), Sumilizer GA-80 (Sumizer GA-80, manufactured by Sumitomo Chemical), Sumitizer GS (Sumizer GS, manufactured by Sumitomo Chemical), Vitamin E (Eisai) Made) It is below. Among these, it is particularly preferable to use Irganox 1010, Irganox 1076, Sumilizer GS, or the like. These may be used alone or in combination of two or more.
Examples of phosphorus antioxidants include tris (2,4-di-t-butylphenyl) phosphite and bis (2,4-bis (1,1-dimethylethyl) -6-methylphenyl) ethyl. Ester phosphorous acid, tetrakis (2,4-di-t-butylphenyl) (1,1-biphenyl) -4,4′-diylbisphosphonite, bis (2,4-di-t-butylphenyl) Pentaerythritol diphosphite, bis (2,6-di-t-butyl-4-methylphenyl) pentaerythritol diphosphite, bis (2,4-dicumylphenyl) pentaerythritol diphosphite, tetrakis (2,4- t-butylphenyl) (1,1-biphenyl) -4,4′-diylbisphosphonite, di-t-butyl-m-cresyl-phosphonite, etc. It is below.
Furthermore, a commercially available phosphorus antioxidant may be used as the phosphorus antioxidant, and such a commercially available phosphorus antioxidant is not particularly limited. For example, Irgaphos 168 (Irgafos 168: Tris (2,4-di-t-butylphenyl) phosphite, manufactured by Ciba Specialty Chemicals), Irgafos 12 (Irgafos 12: Tris [2-[[2,4,8,10-tetra -T-butyldibenzo [d, f] [1,3,2] dioxaphosphine-6-yl] oxy] ethyl] amine, manufactured by Ciba Specialty Chemicals), Irgafos 38 (Irgafos 38: Bis ( 2,4-bis (1,1-dimethylethyl) -6-methylphenyl) ethyl ester phosphorous acid, manufactured by Ciba Specialty Chemicals ), ADK STAB 329K (ADK STAB 329K, manufactured by Asahi Denka), ADK STAB PEP36 (ADK STAB PEP36, manufactured by Asahi Denka), ADK STAB PEP-8 (ADK STAB PEP-8, manufactured by Asahi Denka), Sandstab P-EPQ (manufactured by Clariant) Weston 618 (manufactured by Weston 618, manufactured by GE), Weston 619G (manufactured by Weston 619G, manufactured by GE), Ultranox 626 (manufactured by Ultranox 626, manufactured by GE), Sumilyzer GP (manufactured by Sumitizer GP, manufactured by Sumitomo Chemical), and the like. These may be used alone or in combination of two or more.
The blending amount of the heat stabilizer may be an amount that exhibits the effect of the present invention, and if it is excessively added, problems such as bleeding out during processing may occur. The amount is preferably 5 parts by mass or less, more preferably 3 parts by mass or less, still more preferably 1 part by mass or less, still more preferably 0.8 parts by mass or less, and still more preferably 0.01 parts by mass. It is 0.8 parts by mass or more.

The ultraviolet absorber is not particularly limited, and examples thereof include benzotriazole compounds, benzotriazine compounds, benzoate compounds, benzophenone compounds, oxybenzophenone compounds, phenol compounds, oxazole compounds, and malons. Examples include acid ester compounds, cyanoacrylate compounds, lactone compounds, salicylic acid ester compounds, benzoxazinone compounds, and the like. In particular, benzotriazole compounds and benzotriazine compounds are preferable. These may be used alone or in combination of two or more.
From the viewpoint of ensuring good moldability of the methacrylic resin composition, the ultraviolet absorber preferably has a vapor pressure (P) at 20 ° C. of 1.0 × 10 ⁻⁴ Pa or less. It is more preferably 10 ⁻⁶ Pa or less, and further preferably 1.0 × 10 ⁻⁸ Pa or less.
Here, good moldability means that, for example, when a film is formed, there is little adhesion of a low molecular compound to a roll. When it adheres to the roll, it reattaches to the surface, which causes the appearance to deteriorate and the optical characteristics to deteriorate.
The melting point (Tm) of the ultraviolet absorber is preferably 80 ° C. or higher, more preferably 100 ° C. or higher, further preferably 130 ° C. or higher, and even more preferably 160 ° C. or higher. preferable.
The ultraviolet absorber preferably has a weight reduction rate of 50% or less, more preferably 30% or less, and more preferably 15% or less when the temperature is increased from 23 ° C. to 260 ° C. at a rate of 20 ° C./min. More preferably, it is more preferably 10% or less, still more preferably 5% or less.
The blending amount of the ultraviolet absorber is not particularly limited as long as the effect of the present invention is exerted. However, if the blending amount is too large, problems such as bleeding out during processing may occur. Therefore, the amount is preferably 5 parts by mass or less, more preferably 3 parts by mass or less, still more preferably 1 part by mass or less, still more preferably 0.8 parts by mass or less, and even more preferably 100 parts by mass of methacrylic resin. Preferably they are 0.01 mass part or more and 0.8 mass part or less.

(Processing of methacrylic resin and methacrylic resin composition)
Examples of methods for processing a methacrylic resin composition, or mixing various additives of the methacrylic resin and other resins to process a methacrylic resin composition include, for example, an extruder, a heating roll, a kneader, and a roller mixer. And a kneading method using a kneading machine such as a Banbury mixer.
Among these, kneading with an extruder is preferable in terms of productivity.
The kneading temperature may be in accordance with the preferred processing temperature of the polymer constituting the methacrylic resin and other resins to be mixed, and is generally in the range of 140 to 300 ° C, preferably in the range of 180 to 280 ° C.

[Manufacturing Method for Vehicle Member]
A desired vehicle member can be obtained by molding the above methacrylic resin alone or by molding the methacrylic resin composition containing the methacrylic resin.
As a method for manufacturing a vehicle member, it can be molded by a known method such as injection molding, sheet molding, blow molding, injection blow molding, inflation molding, T-die molding, press molding, extrusion molding, foam molding, or the like. Secondary processing molding methods such as pressure molding, vacuum molding, and press stretching molding can also be used.
Another example is a method in which a resin composition is kneaded and produced using a kneader such as a heating roll, kneader, Banbury mixer, extruder, etc., then cooled, pulverized, and further molded by transfer molding, injection molding, compression molding, or the like. Can be mentioned.

[Characteristics as vehicle components]
In a vehicle member, it is necessary that high heat resistance, transparency, impact resistance, and distortion under high temperature and high humidity conditions are hardly observed.
In addition, when a material with high birefringence is used at the time of molding, since polarized light is seen when passing through a polarizing plate, the instrument cover passes through a polarizing plate such as sunglasses especially when used as a vehicle instrument cover. When this is viewed, the visibility is lowered, which is not preferable. In order to solve such problems, it is necessary to suppress polarization by increasing the molding processing temperature and improve the visibility, and further, it is necessary that defects such as silver do not occur even at a high molding processing temperature.

(Heat-resistant)
The heat resistance of the vehicle member of the present embodiment is good as a practical characteristic if there is no problem such as distortion in the molded product during actual use. Specifically, the VICAT softening temperature is 114 ° C. or higher. Preferably there is. More preferably, it is 115 degreeC or more, More preferably, it is 117 degreeC or more, Most preferably, it is 120 degreeC or more. The VICAT softening temperature can be measured according to ISO 306 B50, and specifically, can be measured by the method described in Examples described later.

(transparency)
The transparency of the vehicle member according to the present embodiment is preferably 70% or more of the total light transmittance at a thickness of 3 mm from the viewpoint of the visibility of the instrument in a member requiring transparency, particularly an instrument cover application. More preferably, it is 75% or more, More preferably, it is 80% or more.
Specifically, the transparency can be measured by the method described in Examples described later.

(Impact resistance)
The impact resistance of the vehicle member of the present embodiment can be measured by measuring the Charpy impact strength (no notch). The Charpy impact strength (no notch) can be measured using a test piece having a thickness of about 3.2 mm in accordance with the ISO 179 standard. The Charpy impact strength when used in a vehicle member application is preferably ²⁰ kJ / m ² or more.

(Thickness)
What is necessary is just to select the thickness of the molded article in the vehicle member of this embodiment in consideration of the weight, strength, and moldability of the molded article. Specifically, it is preferably 0.1 to 5 mm. More preferably, it is 0.5-4 mm, More preferably, it is 0.5-3 mm, Most preferably, it is 1-3 mm. The thickness is preferably 0.1 mm or more from the viewpoint of workability and strength, and preferably 5 mm or less from the viewpoint of workability and molded product weight.

(Moisture and heat resistance)
When used as a vehicle member, depending on the use conditions of the vehicle, it may be placed under high temperature and high humidity conditions. In such a case, depending on the installation location of the vehicle member, the conventional acrylic resin may cause defects such as warpage and distortion.
Therefore, the vehicle member of the present embodiment is warped, distorted, etc. when left for 500 hours at a set temperature of 90 ° C. and a set humidity of 95%, particularly as an evaluation of moisture and heat resistance that can be used for a vehicle instrument cover. It is preferable that no defects occur.
Specifically, the heat and moisture resistance can be measured by the method described in Examples described later.

(Molding processability)
When a resin or resin composition having a large birefringence is molded, when looking through a polarizing glass such as sunglasses, an interference pattern may be seen due to distortion during molding. If it does so, since it becomes difficult to see the instrument installed in an inside, it is not preferable. As a method of eliminating the molding distortion, it is possible to eliminate to some extent by raising the molding temperature and lowering the melt viscosity, but if the molding temperature is raised, the silver is called silver streak in the molded piece. Scratches may occur.
Even when the resin or resin composition used for producing the vehicle member of the present embodiment is molded by raising the molding temperature and lowering the melting temperature in order to eliminate molding distortion, there is no defect such as silver. It is preferable. Specifically, when molding is continuously performed for 50 shots at a barrel temperature of 290 ° C. and a mold temperature of 70 ° C., it is preferable that almost no molding defects such as silver streaks are observed.
Specifically, the moldability can be evaluated by the method described in Examples described later.

[Use]
The member for vehicles of this embodiment can be used conveniently for various uses.
For example, it can be suitably used as vehicle instrument covers for automobiles and motorcycles such as meter panels, vehicle head-up display applications, and vehicle parts applications such as head lamp covers, rear lamp covers, rear combination lamp covers, visors, and bug guards. it can.

  Hereinafter, although a specific Example and a comparative example are given and demonstrated, this invention is not limited to these.

〔material〕
It shows below about the raw material used in the Example and comparative example which are mentioned later.
(A) Component: Methyl methacrylate (MMA)
: Asahi Kasei Chemicals Co., Ltd. (2.5 ppm of 2,4-di-6-tert-butylphenol as a polymerization inhibitor, manufactured by Chugai Trading Co., Ltd.) Added)
(B) component:
(B-1): N-phenylmaleimide (NPMI)
: Nippon Shokubai Co., Ltd. (B-2): N-cyclohexylmaleimide (NCyMI)
: Nippon Shokubai Co., Ltd. (C) component:
(C-1): Styrene (St): Asahi Kasei Chemicals Corporation (C-2-1): Methyl acrylate (MA)
: Made by Mitsubishi Chemical Corporation (14-ppm of 4-methoxyphenol made by Kawaguchi Chemical Industry is added as a polymerization inhibitor)
(C-2-2): Ethyl acrylate (EA): Mitsubishi Chemical Corporation (C-3): Acrylonitrile (AN): Asahi Kasei Chemicals Corporation (D) Component:
(D-1): Maleic anhydride (MAH): manufactured by Mitsui Chemicals, Inc. (used as a copolymerization component)

n-octylmercaptan: manufactured by Arkema Co., Ltd. Lauroyl peroxide: manufactured by Nippon Oil & Fats Co., Ltd. Tribasic calcium phosphate: manufactured by Nippon Chemical Industry Co., Ltd., suspended Calcium carbonate (calcium calbonate): Shiraishi Kogyo Co., Ltd., used as suspending agent sodium lauryl sulfate: Wako Pure Chemical Industries, Ltd., used as suspending aid

[Measurement method]
(I. Measurement of molecular weight)
<1. Molecular weight measurement of methacrylic resin>
The weight average molecular weight and molecular weight distribution of the methacrylic resin were measured with the following apparatus and conditions.
Measuring device: Tosoh Corporation gel permeation chromatography (HLC-83)
20GPC) Column: One TSK guard column SuperH-H, two TSK gel Super HM-Ms, and one TSK gel Super H 2500 were connected in series in this order.
In this column, the high molecular weight elutes early and the low molecular weight elutes slowly.
Detector: RI (differential refraction) detector Detection sensitivity: 3.0 mV / min
Column temperature: 40 ° C
Sample: 0.02 g of methacrylic resin in 20 mL of tetrahydrofuran Injection amount: 10 μL
Developing solvent: Tetrahydrofuran, flow rate; 0.6 mL / min
As an internal standard, 2,6-di-t-butyl-4-methylphenol (BHT) was added at 0.1 g / L.
The following 10 polymethyl methacrylates (manufactured by Polymer Laboratories; PMMA Calibration Kit M-M-10) having different molecular weights and known monodisperse weight peak molecular weights were used as standard samples for calibration curves.
Weight peak molecular weight (Mp)
Standard sample 1 1,916,000
Standard sample 2 625,500
Standard sample 3 298,900
Standard sample 4 138,600
Standard sample 5 60,150
Standard sample 6 27,600
Standard sample 7 10,290
Standard sample 85,000
Standard sample 9 2,810
Standard document 10 850
Under the above conditions, the RI detection intensity with respect to the elution time of the methacrylic resin was measured.
Based on the area area in the GPC elution curve and a calibration curve of a seventh-order approximation formula, a methacrylic resin (
The weight average molecular weight (Mw) and molecular weight distribution (Mw / Mn) of A) were determined.

(II. Measurement of Aggregate Production)
The mixed solution containing polymer fine particles obtained by polymerization is passed through a 1.68 mm mesh sieve to remove fine particle aggregates, and the obtained aggregates are dried in a drying oven at 80 ° C. for 12 hours, and then the weight is measured. It was measured.

(III. Measurement of angle of repose)
The angle of repose of the polymer fine particles was measured using a powder tester manufactured by Hosokawa Micron Corporation.

(IV. Measurement of average particle diameter)
Based on JIS-Z8801, sieves (Tokyo Screen JTS-200-45-44 (aperture 500 μm), 34 (aperture 425 μm), 35 (aperture 355 μm), 36 (aperture 300 μm), 37 (aperture 250 μm) ), 38 (aperture 150 μm), 61 (a saucer)), and the weight of particles remaining on each sieve when sieving for 10 minutes with vibration force MAX using a sieving tester TSK B-1 And the average particle diameter of polymer fine particles was calculated | required by calculating | requiring the particle diameter when a weight will be 50%.

(V. Physical property measurement)
<1. Heat resistance; measurement of VICAT softening temperature>
In accordance with ISO 306 B50, measurement is performed using a 4 mm-thick test piece molded using resin pellets obtained in Examples and Comparative Examples described later, and the VICAT softening temperature (° C.) is obtained. And evaluated according to the following criteria.
VICAT softening temperature of 117 ° C or higher: "○"
114 ° C. or higher and lower than 117 ° C .: “△”
Less than 114 ° C: “×”

<2. Transparency; Measurement of total light transmittance>
Based on the ISO 13468-1 standard, the total light transmittance was measured using a 3 mm-thick test piece molded using resin pellets obtained in Examples and Comparative Examples described later, and used as an index of transparency. .

<3. Moist heat resistance test>
Using resin pellets obtained in Examples and Comparative Examples described later and using a hot press machine, 280 ° C., 0 kgf / cm ² for 2 minutes, 280 ° C./10 kgf / cm ² for 10 minutes, 280 ° C./40 kgf A press test piece having a thickness of about 3 mm, a width of 30 mm, and a length of 30 mm was prepared by holding at / cm ² for 2 minutes, and left in a constant temperature and humidity chamber set at a temperature of 90 ° C. and a humidity of 95% for 500 hours. The shape of the test piece was observed and evaluated according to the following criteria.
Deformation such as distortion: “×”
Slightly deformed: “△”
Almost no deformation: “○”

<5. Visibility>
Using a sample dried in a steam oven set at 85 ° C. for 8 hours, using a hot press, 280 ° C., 0 kgf / cm ² for 2 minutes, 280 ° C./10 kgf / cm ² for 10 minutes, 280 ° C. / By holding at 40 kgf / cm ² for 2 minutes, a press test piece having a thickness of about 3 mm × width 30 mm × length 30 mm was produced, and the test piece was placed on a polarizing film (registered trademark TECH) with a light source placed behind it. SPEC) and evaluated according to the following criteria.
Many interference patterns were seen: “×”
What was not seen so much: “○”

<6. Impact resistance>
Charpy impact strength (no notch): Measured using a test piece having a thickness of about 3.2 mm, which was molded using resin pellets obtained in Examples and Comparative Examples described later, in accordance with ISO 179 standard. Evaluation was performed according to the criteria.
Less than 20 kJ / m ² : “×”
20 kJ / m ² or more: “○”

<7. Overall evaluation>
One with high heat resistance, no distortion in the molded piece even under high-temperature and high-humidity conditions, silver is not generated during molding, and high visibility when viewed through polarizing glass Evaluations were made with “x” indicating that even one item was defective.

Hereinafter, a method for producing a methacrylic resin will be described.
The blending amounts are shown in Table 1 below.
Table 2 below shows the monomer charge composition, the measurement results of the weight average molecular weight, and the polymerization conditions.

[Example 1]
In a vessel equipped with a stirrer, 84% by mass of methyl methacrylate (MMA), 10% by mass of N-phenylmaleimide (B-1), 6% by mass of styrene (St) are mixed, and the total amount of monomers is 100 parts by mass. To this, 0.03 parts by mass of lauroyl peroxide and 0.045 parts by mass of n-octyl mercaptan were added and dissolved to prepare a monomer mixture.
The outer periphery of two glass plates with a size of 250 x 300 mm and a thickness of 6 mm is attached with a flexible vinyl chloride gasket so that the distance between the two glass plates is 3.5 mm. Assemble the cell. The monomer mixture solution was devolatilized for 2 minutes while continuing to stir at a reduced pressure of 50 torr. After releasing the reduced pressure and returning to normal pressure, the mixture was immediately poured into a prepared glass cell and filled.
Next, the glass cell filled with the monomer compound solution is held in a hot water bath adjusted to 60 to 65 ° C. for 20 hours, and then kept in a hot air circulation oven adjusted to 120 ° C. for 3 hours, and then is kept indoors. The glass cell was disassembled and the glass plate was removed to obtain a sheet-like resin. The obtained sheet-like resin is pulverized with a coarse pulverizer Orient Mill VM-42D manufactured by Seishin Enterprise Co., Ltd., to which a 10 mm mesh net is attached. Got. The recovery rate of the pulverized product was 93.4%.
Mw and Mw / Mn of the obtained pulverized composition were Mw: 500,000 and Mw / Mn: 2.1, respectively.
The obtained pulverized composition was melt-kneaded with a φ30 mm twin-screw extruder set at 280 ° C., and the strands were cooled and cut to obtain resin pellets. It was confirmed that the extrusion workability at that time was good.

[Example 2]
In a container equipped with a stirrer, 80% by mass of methyl methacrylate (MMA), 12% by mass of N-phenylmaleimide (B-1), 8% by mass of styrene (St) are mixed, and the total amount of monomers is 100 parts by mass. To this, 0.026 parts by mass of lauroyl peroxide and 0.026 parts by mass of n-octyl mercaptan were added and dissolved to prepare a monomer mixture.
The outer periphery of two glass plates with a size of 250 x 300 mm and a thickness of 6 mm is attached with a flexible vinyl chloride gasket so that the distance between the two glass plates is 3.5 mm. Assemble the cell. The monomer mixture solution was devolatilized for 2 minutes while continuing to stir at a reduced pressure of 50 torr. After releasing the reduced pressure and returning to normal pressure, the mixture was immediately poured into a prepared glass cell and filled.
Next, the glass cell filled with the monomer compound solution is held in a hot water bath adjusted to 60 to 65 ° C. for 20 hours, and then kept in a hot air circulation oven adjusted to 120 ° C. for 3 hours, and then is kept indoors. The glass cell was disassembled and the glass plate was removed to obtain a sheet-like resin. The obtained sheet-like resin is pulverized with a coarse pulverizer Orient Mill VM-42D manufactured by Seishin Enterprise Co., Ltd., to which a 10 mm mesh net is attached. Got. The recovery rate of the pulverized product was 92.6%.
Mw and Mw / Mn of the obtained pulverized composition were Mw: 770,000 and Mw / Mn: 2.1, respectively.
The obtained pulverized composition was melt-kneaded with a φ30 mm twin-screw extruder set at 290 ° C., and the strand was cooled and cut to obtain resin pellets. It was confirmed that the extrusion workability at that time was good.

Example 3
2 kg of water, 65 g of tricalcium phosphate, 39 g of calcium carbonate, and 0.39 g of sodium lauryl sulfate were charged into a container having a stirrer equipped with four inclined paddle blades to obtain a mixed solution (a).
Next, 26 kg of water was put into a 60 L reactor equipped with a stirrer equipped with three blades and the temperature was raised to 80 ° C., and the mixture liquid (a) and the methacrylic resin in the blending amount shown in Table 1 below were used. The raw materials were input.
Suspension polymerization was performed while maintaining the temperature at about 75 ° C., and an exothermic peak was observed about 120 minutes after the starting material mixture was charged.
Thereafter, the temperature was raised to 93 ° C. at a rate of 1 ° C./min and then aged for 120 minutes to substantially complete the polymerization reaction.
Next, in order to cool to 50 ° C. and dissolve the suspending agent, 20 mass% sulfuric acid was added.
Next, the polymerization reaction solution is passed through a 1.68 mm mesh sieve to remove aggregates, the water is filtered off, the resulting slurry is dehydrated to obtain a bead polymer, and the resulting bead polymer is After washing with water, it was dehydrated in the same manner as described above, and further washed with ion-exchanged water and repeated dehydration to obtain polymer particles.
The aggregate was dried in an oven at 80 ° C. for 12 hours, weighed, and the weight was divided by the total amount of raw materials, and the aggregate production amount (mass%) was measured to be 0.42 mass%. It was.
The obtained polymer particles were dried in a hot air drying oven at 80 ° C. for 12 hours, and then taken out from the drying oven and measured for an angle of repose after about 1 hour. The angle of repose was 29 degrees, and the average particle size was 0.29 mm. .
The obtained polymer particles were melt-kneaded with a φ30 mm twin-screw extruder set at 280 ° C., and the strands were cooled and cut to obtain resin pellets. It was confirmed that the extrusion workability at that time was good.
Using the obtained pellets, an injection molded product was produced and evaluated.
The evaluation results are shown in Table 2 below.

[Examples 4-8, Comparative Examples 1-3]
Polymerization was performed using the raw materials shown in Table 1 below in the same manner as in Example 3 to obtain polymer particles.
Resin pellets were produced in the same manner as in Example 3 described above. At that time, the extrusion workability was good.
Moreover, the physical property measurement result of the molded body of the methacrylic resin of Examples 4 to 8 and Comparative Examples 1 to 3 is shown in Table 2 below.

[Comparative Example 4]
In a container equipped with a stirrer, 78% by mass of methyl methacrylate (MMA), 14% by mass of styrene, and 8% by mass of maleic anhydride were mixed, and the total amount of monomers was 100 parts by mass. To this was added lauroyl peroxide 0.03. Mass parts and 0.072 parts by mass of n-octyl mercaptan were added and dissolved to prepare a monomer compounding solution.
On the other hand, two glass plates having a size of 250 × 300 mm and a thickness of 6 mm are used, and the vicinity of the outer periphery is bonded with a flexible vinyl chloride gasket, and the distance between the two glass plates is 3.5 mm. A cell was prepared and prepared.
A devolatilization operation for 2 minutes was performed while stirring the monomer blend solution described above under a reduced pressure of 50 torr. Thereafter, the reduced pressure was released to restore the normal pressure, and the glass cell was immediately poured to fill.
Next, it is kept in a hot water tank adjusted to 60 to 65 ° C. for 22 hours, and then kept in a hot-air circulating oven adjusted to 120 ° C. for 3 hours, and then allowed to stand and cool indoors to remove the glass plate. A sheet-like resin was obtained.
The sheet-like resin obtained as described above was pulverized with a coarse pulverizer Orient Mill VM-42D machine manufactured by Seishin Enterprise Co., Ltd. equipped with a 10 mm mesh net, and then the pulverized product was passed through a 500 μm sieve, Fine powder was removed to obtain a pulverized composition.
The recovery rate of the pulverized composition was 93.2%.
The obtained pulverized composition was melt-kneaded with a φ30 mm twin-screw extruder set at 280 ° C., and the strands were cooled and cut to obtain resin pellets. At that time, extrusion workability due to surging or the like was poor. Using the obtained pellets, an injection molded product was produced and evaluated.
The evaluation results are shown in Table 2 below.

  In Table 1, the blending amounts of Examples 3 to 8 and Comparative Examples 1 to 3 to which the suspension polymerization method was applied are described, and for Examples 1 and 2 and Comparative Example 4 to which the bulk polymerization method was applied, Table 2 below shows only the blending ratio.

  In Examples 1-8, it had sufficient heat resistance, and the transparency, impact resistance, and heat-and-moisture resistance required for a vehicle instrument cover were also good.

  The vehicle member of the present invention is a vehicle instrument cover for automobiles and motorcycles such as a meter panel, a vehicle head-up display application, and a vehicle component application such as a headlamp cover, rear lamp cover, rear combination lamp cover, visor, and bug guard. As an industrial applicability.

Claims (9)

Methacrylic acid ester monomer unit (A): 70 to 95% by mass,
Maleimide monomer unit (B): 5 to 30% by mass
Containing,
The member for vehicles containing the methacrylic resin whose weight average molecular weight measured by gel permeation chromatography (GPC) exceeds 300,000 and is 1,000,000 or less.   The vehicle member according to claim 1, wherein the maleimide monomer (B) is N-cyclohexylmaleimide and / or N-phenylmaleimide.   A methacrylic resin further containing another vinyl monomer unit (C) copolymerizable with the methacrylic acid ester monomer unit (A) and the maleimide monomer (B). The vehicle member according to 2.   The other vinyl monomer units (C) copolymerizable with (A) and (B) are a group consisting of an aromatic vinyl monomer, an acrylate monomer, and a vinyl cyanide monomer. The member for vehicles according to claim 3 which is at least one sort chosen from.   The other vinyl monomer units (C) copolymerizable with the (A) and (B) are at least one selected from the group consisting of methyl acrylate, ethyl acrylate, styrene, and acrylonitrile. The member for vehicles as described in 3 or 4. The methacrylic resin is
For a total amount of 100 parts by mass of the methacrylic acid ester monomer unit (A) and the maleimide monomer unit (B),
Containing 0 to 30 parts by mass of other vinyl monomer units (C) copolymerizable with (A) and (B),
The vehicle member according to any one of claims 3 to 5.   The member for vehicles as described in any one of Claims 1 thru | or 6 whose thickness is 0.1-5 mm.   The member for vehicles according to any one of claims 1 to 7 whose VICAT softening temperature of said methacrylic resin is 117 ° C or more.   The member for vehicles according to any one of claims 1 to 8 which is an instrument cover for vehicles.