JP2023061155A - Olefin modified acrylic resin, resin composition, coating composition, and coated product of these - Google Patents

Abstract

To provide an olefin modified acrylic resin which enables provision of a resin composition having excellent storage stability without generating gelation in a method for grafting an acrylic component into a polyolefin component, the resin composition, a coating composition, and a coated product of these.SOLUTION: An olefin modified acrylic resin has a chemical structure represented by the general formula (1). In the formula, R11 and R12 independently represent a hydrogen atom or a chlorine atom, R21 represents an alkylene group having 1 to 6 carbon atoms, R31 and R32 each independently represent a hydrogen atom or a methyl group, R41 and R42 each independently represent an alkyl group having 1 to 18 carbon atoms that may be substituted with a hydrogen atom, a hydroxyl group, an amine group, an alkoxy group and a carbonyl group, and an aliphatic or aromatic ring having 3 to 6 carbon atoms, and R51 to R53 each independently represent a hydrogen atom or a methyl group.SELECTED DRAWING: None

Description

TECHNICAL FIELD The present invention relates to coating materials, particularly olefin-modified acrylic resins, resin compositions, coating compositions, and coatings thereof, which are used for coating plastic substrates.

Conventionally, resin compositions containing acrylic copolymers have been widely used for applications such as paints, inks, adhesives, and synthetic leather, due to their excellent weather resistance, flexibility, strength, and adhesiveness. there is Especially in the application of coatings, resin compositions containing various acrylic copolymers that meet the required performance for coating various materials in the fields of automobiles, home appliances, building materials, etc. have been provided. there is

In addition, demand for plastics is increasing as a material for substrates to be coated for the purpose of weight reduction, cost reduction, and other purposes. Among them, polyolefin-based resins such as polyethylene and polypropylene are characterized by moldability, weight reduction, low cost, recyclability, and the like, and are increasingly used for automobile parts, home electric appliances, and the like.
However, since polyolefin resins generally have high crystallinity and low polarity, they have the disadvantage that paints, printing inks, adhesives, etc. are difficult to adhere to them. In order to solve such drawbacks, conventionally, the substrate surface has been subjected to physical treatments such as polishing, chemical treatments such as chromic acid mixtures and solvents, other pretreatments such as plasma treatment and corona discharge treatment, and primer compositions. A method of painting has been proposed.

Also, paints made from resin compositions containing chlorinated polyolefins have been used for a long time. Further, in order to impart the durability of the coating film and the adhesion to the top coat, it has been proposed to combine a polyolefin component and an acrylic component. However, such a resin composition has poor storage stability when dissolved in an organic solvent to form a varnish, and tends to separate or aggregate over time.

In response to such problems, for example, Patent Document 1 discloses that a (meth)acrylic ester having one hydroxyl group is ester-bonded to an acid-modified chlorinated polyolefin, and then a (meth)acrylic acid-based monomer is added. It has been proposed to chemically bond by graft copolymerization to improve storage stability.

Japanese Patent Application Laid-Open No. 2002-309161

When the (meth)acryloyl group of the graft copolymer obtained by grafting the acrylic component to the polyolefin component as described above is copolymerized with the (meth)acrylic acid-based monomer, the structure of the bridge with the nearby olefin molecule Then, gelation occurs. If a large amount of initiator is used for polymerization so as not to cause gelation, the molecular weight becomes low, making it difficult to control the production process and to prepare the desired physical properties.

The present invention has been made in view of the above circumstances, and it is possible to provide a resin composition having excellent storage stability without causing gelation in a method of grafting an acrylic component to a polyolefin component. An object of the present invention is to provide an olefin-modified acrylic resin, the resin composition, a coating composition, and coated products thereof.

The present invention has the following aspects.
[1] An olefin-modified acrylic resin having a chemical structure represented by the following general formula (1), in which an olefin resin and an acrylic resin are bonded via a sulfur element.

In formula (1), R ¹¹ and R ¹² each independently represent a hydrogen atom or a chlorine atom, R ²¹ represents a linear or branched C 1-6 alkylene group, R ³¹ , R ³² each independently represents a hydrogen atom or a methyl group, and R ⁴¹ and R ⁴² each independently represents a linear or branched chain optionally substituted with a hydrogen atom, hydroxyl group, amine group, alkoxy group or carbonyl group. each of R ⁵¹ to R ⁵³ independently represents a hydrogen atom or a methyl group.

[2] The olefin-modified acrylic resin of the above [1], which is a reaction product of the olefin resin and an acrylic resin having a terminal hydroxyl group derived from mercapto alcohol.
[3] The olefin-modified acrylic resin of [1] above, which is a reaction product of an olefin resin having a terminal mercapto group derived from a mercapto alcohol and the acrylic resin.
[4] The olefin-modified acrylic resin of [2] or [3], wherein the mercaptoalcohol is mercaptoethanol or mercaptobutanol.
[5] The olefin resin is an acid anhydride-modified olefin resin,
The above [2] to [4], wherein the chemical structure derived from the hydroxyl group of the mercapto alcohol is 0.6 to 2.5 mol per 1 mol of the acid anhydride-derived chemical structure of the acid anhydride-modified olefin resin. ] any one of the olefin-modified acrylic resin.
[6] The olefin resin is an olefin resin modified with an acid anhydride,
The above [1] to [5], wherein the mass ratio of the acid anhydride-derived chemical structure to the total mass of the acid anhydride-modified olefin resin-derived chemical structure is 1.7 to 5.0%. Any olefin-modified acrylic resin.
[7] The olefin-modified acrylic resin of [5] or [6], wherein the acid anhydride is maleic anhydride.
[8] A resin composition comprising the olefin-modified acrylic resin according to any one of [1] to [7] and an acrylic resin not bound to an olefin.
[9] A coating composition comprising the resin composition of [8].
[10] A coated article comprising a coating film formed from the resin composition of [8] or the coating composition of [9] on the surface of a plastic substrate.

According to the present invention, an olefin-modified acrylic resin that can provide a resin composition having excellent storage stability without causing gelation in a method of grafting an acrylic component to a polyolefin component, and the resin composition. , coating compositions and coated articles thereof can be provided.

<Olefin-modified acrylic resin (GP) and its production method>
The olefin-modified acrylic resin (GP) of the present invention comprises an olefin resin (O) (hereinafter also abbreviated as "(O) component") and an acrylic resin (A) (hereinafter also abbreviated as "(A) component"). ) are bonded via a sulfur element, and have a chemical structure represented by the following general formula (1).

In formula (1), R ¹¹ and R ¹² each independently represent a hydrogen atom or a chlorine atom, R ²¹ represents a linear or branched C 1-6 alkylene group, R ³¹ , R ³² each independently represents a hydrogen atom or a methyl group, and R ⁴¹ and R ⁴² each independently represents a linear or branched chain optionally substituted with a hydrogen atom, hydroxyl group, amine group, alkoxy group or carbonyl group. each of R ⁵¹ to R ⁵³ independently represents a hydrogen atom or a methyl group.
In addition, in Formula (1), a wavy line shows a bond.

The method for producing the olefin-modified acrylic resin (GP) of the present invention is not particularly limited as long as it is a method capable of obtaining the olefin-modified acrylic resin (GP) of the present invention. post-addition method), production method 2 (pre-addition method), and the like.
Production method 1 (post-addition method): Using mercapto alcohol (hereinafter also abbreviated as "(MA) component"), after synthesizing acrylic resin (A1) having a terminal hydroxyl group derived from the (MA) component, , by esterifying the acid anhydride of the olefin resin (Oa) modified with the acid anhydride with the hydroxyl group of the acrylic resin (A1) having a terminal hydroxyl group derived from the (MA) component, the acid anhydride-modified A method for obtaining an olefin-modified acrylic resin (GP), which is a reaction product (1) of the olefin resin (Oa) and the hydroxyl-terminated acrylic resin (A1) derived from the component (MA).
The acid anhydride-modified olefin resin (Oa) referred to in production method 1 (post-addition method) is the olefin resin (Oa2) having no mercapto group derived from the component (MA) in the side chain.

Production method 2 (pre-addition method): After esterifying the hydroxyl group of the (MA) component to the acid anhydride of the acid anhydride-modified olefin resin (Oa), the mercapto group derived from the (MA) component is added. by radically polymerizing a (meth)acrylic acid-based monomer using an olefin resin (Oa1) modified with an acid anhydride and having a mercapto group derived from the (MA) component in a side chain, and an acrylic resin ( A method for obtaining an olefin-modified acrylic resin (GP) which is a reaction product (2) with A).
The acrylic resin (A) referred to in production method 2 (pre-addition method) is the acrylic resin (A2) having no terminal hydroxyl group derived from the component (MA).

In either method, the olefin resin (O) and the acrylic resin (A) are chemically bonded via the sulfur element, so the resin composition containing the olefin-modified acrylic resin (GP) of the present invention is a varnish. The storage stability in the state of (organic solvent solution) becomes good.

The reaction product (1) obtained in production method 1 (post-addition method) and the reaction product (2) obtained in production method 2 (pre-addition method) are an acid anhydride-modified olefin resin (Oa) and an acrylic resin. and (A) are bonded via a divalent group —R ²¹ —S—.
R ²¹ in the divalent group is a linear or branched alkylene group having 1 to 6 carbon atoms and corresponds to R ²¹ in general formula (2).
The divalent group is derived from the (MA) component. That is, the mercaptoalcohol used in production method 1 (post-addition method) and production method 2 (pre-addition method) is a compound represented by HO--R ²¹ --SH.

The olefin-modified acrylic resin (GP) has an increased degree of freedom in the timing of adding a mercapto group, which serves as a chain transfer agent, in the polymerization process of the acrylic resin (A), thereby facilitating molecular weight control. ) is preferred.
In addition, the olefin-modified acrylic resin (GP) is preferably the reactant (2) because it is difficult to gel even if a monomer containing a hydroxyl group is used in the polymerization step of the acrylic resin (A).

In the olefin resin (Oa) modified with an acid anhydride, grafting to the olefin resin (Oa) is easy, and the esterification reaction between an alcohol and an acid anhydride is facilitated. Maleic anhydride is preferred.

The weight-average molecular weight of component (O) is not particularly limited, but is preferably from 40,000 to 200,000. If the weight-average molecular weight of component (O) is 40,000 or more, chemical resistance such as resistance to staining of cosmetics and adherence to substrates will be good, and if it is 200,000 or less, storage stability of the resin composition will be good. be better.
In this specification, the "weight average molecular weight of the (O) component" does not include the molecular weight of the chemical structure derived from the (MA) component.
Moreover, in this specification, a "weight average molecular weight" is a standard polystyrene conversion value by the gel permeation chromatography method.

The mass ratio of the acid anhydride-derived chemical structure to the total mass of the acid anhydride-modified olefin resin (Oa)-derived chemical structure is preferably 1.7 to 5.0%. If the mass ratio of the chemical structure derived from the acid anhydride is 1.7% or more, the storage stability of the resin composition becomes better, and if it is 5.0% or less, the resin composition is applied and formed. The water resistance of the coating film becomes good.

The (O) component is preferably an acid anhydride-modified olefin resin (Oa).
Specific examples of the acid anhydride-modified olefin resin (Oa) include maleic anhydride-modified polypropylene resin, maleic anhydride-modified polyethylene resin, and maleic anhydride-modified chlorinated polypropylene resin. Commercially available products can also be used as these resins.

The mass ratio of the chemical structure derived from the (O) component to the total mass of the chemical structure of the olefin-modified acrylic resin (GP) is 5 to 30% from the viewpoint of the storage stability of the resin composition and the adhesion to the polyolefin substrate. is preferred, and 10 to 20% is more preferred. If the mass ratio of the chemical structure derived from the component (O) is 5% or more, the adhesion to the polyolefin substrate is improved, and if it is 30% or less, the storage stability of the resin composition is improved.
In this specification, the mass ratio of the chemical structure derived from the (O) component does not include the mass of the chemical structure derived from the (MA) component.

The unsaturated monomer constituting component (A) is preferably an unsaturated monomer chain-transferred by the mercapto group of the mercaptoalcohol. In particular, when the olefin-modified acrylic resin (GP) is produced by the post-addition method of production method 1, it is preferred that the unsaturated monomers constituting component (A) do not contain hydroxyl groups.

Examples of unsaturated monomers constituting component (A) include methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, i-propyl (meth) acrylate, n-butyl (meth) acrylate, ) acrylate, i-butyl (meth) acrylate, sec-butyl (meth) acrylate, t-butyl acrylate, 2-ethylhexyl (meth) acrylate, n-octyl (meth) acrylate, n-lauryl (meth) acrylate, n- tridecyl (meth)acrylate, n-stearyl (meth)acrylate, cyclohexyl (meth)acrylate, phenyl (meth)acrylate, benzyl (meth)acrylate, isobornyl (meth)acrylate, 2-methoxyethyl (meth)acrylate, 2-ethoxy ethyl (meth) acrylate, phenoxyethyl (meth) acrylate, 2-(2-ethylhexaoxy) ethyl (meth) acrylate, 1-methyl-2-methoxyethyl (meth) acrylate, 3-methoxybutyl (meth) acrylate, 3-methyl-3-methoxybutyl (meth)acrylate, o-methoxyphenyl (meth)acrylate, m-methoxyphenyl (meth)acrylate, p-methoxyphenyl (meth)acrylate, o-methoxyphenylethyl (meth)acrylate, (meth)acrylic acid ester monomers such as m-methoxyphenylethyl (meth)acrylate and p-methoxyphenylethyl (meth)acrylate; (meth)acrylic acid, 2-(meth)acryloyloxyethylhexahydrophthalic acid, 2-(Meth)acryloyloxypropylhexahydrophthalate, 2-(meth)acryloyloxyethyltetrahydrophthalate, 2-(meth)acryloyloxypropyltetrahydrophthalate, 5-methyl-2-(meth)acryloyloxyethylhexa Hydrophthalic Acid, 2-(Meth)Acryloyloxyethyl Phthalic Acid, 2-(Meth)Acryloyloxypropyl Phthalic Acid, 2-(Meth)Acryloyloxyethyl Maleate, 2-(Meth)Acryloyloxypropyl Maleate, 2- (Meth) acryloyloxyethyl succinate, 2-(meth) acryloyloxypropyl succinate, 2-(meth) acryloyloxyethyl oxalate, 2-(meth) acryloyloxypropyl oxalate, crotonic acid, fumaric acid, maleic acid , itaconic acid, sorbic acid, monomethyl maleate, monomethyl itaconate and their acid anhydrides, vinyl monomers having a carboxyl group and their anhydrides; styrene, α-methylstyrene, vinyltoluene, (meth) Vinyl-based monomers such as acrylonitrile, vinyl acetate, and vinyl propionate; polymerizable unsaturated groups such as α-butyl-ω-(3-methacryloxypropyl)polydimethylsiloxane and polyether-modified polydimethylsiloxane having an acryloyl group polymerizable unsaturated organic silane compounds such as 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropyltriethoxysilane and vinyltrimethoxysilane; and the like.
These may be used individually by 1 type, and may use 2 or more types together.
In this specification, "(meth)acrylate" is a generic term for acrylate and methacrylate. "(Meth)acrylic acid" is a generic term for acrylic acid and methacrylic acid. "(Meth)acryloyl" is a generic term for acryloyl and methacryloyl. "(Meth)acrylonitrile" is a generic term for acrylonitrile and methacrylonitrile.

Examples of unsaturated monomers that can be used in the pre-addition method of production method 2 include 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, and 3-hydroxypropyl (meth)acrylate. acrylate, 2-hydroxybutyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, a (meth)acrylic acid ester monomer having a hydroxyl group such as glycerol (meth)acrylate; 2-hydroxyethyl (meth)acrylate; adducts with ethylene oxide, propylene oxide, γ-butyrolactone or ε-caprolactone; dimers or trimers such as 2-hydroxyethyl (meth)acrylate or 2-hydroxypropyl (meth)acrylate; unsaturated monomers having
These may be used individually by 1 type, and may use 2 or more types together.

The weight average molecular weight of component (A) is preferably 10,000 to 40,000. If the weight average molecular weight of component (A) is 10,000 or more, the chemical resistance and water resistance of the coating film formed by applying the resin composition are improved, and if it is 40,000 or less, the resin composition The amount of volatile organic compounds (VOC) is small and the viscosity of the solution is moderate, so that the handleability of the resin composition is improved.
In this specification, the "weight average molecular weight of component (A)" does not include the molecular weight of the chemical structure derived from component (MA).

The mass ratio of component (O) to component (A) is preferably from 5:95 to 95:5. If the mass ratio of component (O) is 5 or more, adhesion to polyolefin substrates is improved, and if it is 95 or less, the durability of the coating film and adhesion to topcoat paint are improved.
In this specification, the mass ratio of the (O) component to the (A) component does not include the mass of the chemical structure derived from the (MA) component.

The (MA) component contains both a hydroxyl group that esterifies with the acid anhydride of the acid anhydride-modified olefin resin (Oa) and a mercapto group that can undergo a chain transfer reaction during the production of the component (A). Any material can be used. Specific examples of the (MA) component include mercaptoethanol, mercaptobutanol, and mercaptohexanol. The alkylene group (R ²¹ ) connecting the hydroxyl group and the mercapto group is preferably linear and has a large number of carbon atoms from the viewpoint of good reactivity. The alkylene group for R ²¹ preferably has 2 to 6 carbon atoms.
R ²¹ is preferably a linear or branched alkylene group having 2 to 4 carbon atoms, more preferably a linear alkylene group having 2 to 4 carbon atoms, from the viewpoint of easy availability during industrialization. Further preferred are 2 or 4 alkylene groups. Specifically, the (MA) component is preferably mercaptoethanol or mercaptobutanol.
Further, from the viewpoint of good reactivity, the number of carbon atoms in the (MA) component is preferably large, and R ²¹ is preferably a linear or branched alkylene group having 4 to 6 carbon atoms. An alkylene group having 4 to 6 numbers is more preferred, and a straight-chain 4 or 6 alkylene group is even more preferred. Specifically, the (MA) component is preferably mercaptobutanol or mercaptohexanol.

The hydroxyl group-derived chemical structure of the component (MA) is preferably 0.6 to 2.5 mol per 1 mol of the acid anhydride-modified olefin resin (Oa) chemical structure derived from the acid anhydride. (MA) If the chemical structure derived from the hydroxyl group of the component is 0.6 mol or more, the storage stability of the resin composition is further improved, and if it is 2.5 mol or less, the coating formed by applying the resin composition The water resistance of the film is improved.

In the production of the components (O) and (A), the thermal polymerization initiator for radical polymerization is not particularly limited, and ordinary radical polymerization initiators such as organic peroxides and azo compounds can be used.
Examples of organic peroxides include t-butylperoxy 2-ethylhexanoate, benzoyl peroxide, dicumyl peroxide, dibutyl peroxide and the like.
Examples of azo compounds include 2,2′-azobisisobutyronitrile, 2,2′-azobis(2-methylbutyronitrile), 2,2′-azobis(2,4-dimethylvaleronitrile) etc.
Any one of these may be used alone, or two or more thereof may be used in combination.

As the thermal polymerization initiator, an organic peroxide is desirable because of its high cross-linking efficiency.
The amount of the thermal polymerization initiator to be used is appropriately determined depending on the weight-average molecular weight of the target resin, etc., but is usually preferably 0.1 to 3% by mass with respect to the total of 100% by mass of the component (A).
From the viewpoint of improving the reaction rate of the chain transfer reaction by the mercapto group of the component (MA), the amount of the thermal polymerization initiator used is 0.1 to 0.5% by mass with respect to the total 100% by mass of the component (A). is more preferred.

<Resin composition>
The resin composition (B) of the present invention contains the above olefin-modified acrylic resin (GP) of the present invention and an acrylic resin (NA) not bound to olefins.
When the resin composition (B) contains the olefin-modified acrylic resin (GP) and the acrylic resin (NA), the fluidity of the resin solution is improved.

The content of the olefin-modified acrylic resin (GP) is preferably 5 to 95% by mass, more preferably 10 to 50% by mass, based on the total mass of the resin composition (B). If the content of the olefin-modified acrylic resin (GP) is 5% by mass or more, the adhesion to the polyolefin substrate is improved, and if it is 95% by mass or less, the fluidity of the resin solution is improved.

The acrylic resin (NA) is not particularly limited as long as it is not olefin-modified acrylic resin, and examples thereof include acrylic resins other than olefin-modified acrylic resin (GP).
Acrylic resin (NA) is obtained by polymerizing acrylic monomers by a known method.
Examples of acrylic monomers constituting the acrylic resin (NA) include the unsaturated monomers constituting the component (A) exemplified above in the description of the olefin-modified acrylic resin (GP).

The resin composition (B) may contain an organic solvent.
The organic solvent is not particularly limited as long as it can dissolve each component, but examples include aromatic solvents such as toluene, xylene, and other high-boiling aromatic solvents; -) Ester solvents such as butyl, isobutyl acetate, ethyl acetate, propyl acetate, cellosolve acetate; ketone solvents such as methyl ethyl ketone, methyl isobutyl ketone, methyl amyl ketone, diacetone alcohol, cyclohexanone, and isophorone; alcohol solvents such as n-butanol and isobutanol; hydrocarbon solvents such as Supersol 100 (manufactured by Nippon Oil Co., Ltd., product name) and cyclohexane;
These may be used individually by 1 type, and may use 2 or more types together.

The resin composition (B) can be applied to various paints such as clear paints, mixed paints such as coloring pigments and matting agents, and metallic paints containing aluminum flakes. It can be used for plastic moldings in a wide range of applications. In particular, it can be suitably used for difficult-to-paint plastics such as polyolefin resins such as polyethylene and polypropylene, which have been difficult to paint due to poor adhesion of the coating film. A coating film having various excellent properties such as alcohol resistance, oil resistance and adhesion can be formed. Moreover, the resin composition (B) is excellent in storage stability in the form of a varnish (organic solvent solution) even if it does not contain an aromatic organic solvent.

The resin composition (B) is obtained by mixing an olefin-modified acrylic resin (GP), an acrylic resin (NA), and, if necessary, an organic solvent.
In the production method 1 (post-addition method) or production method 2 (pre-addition method) described above, part of the acrylic resin (A) may remain without reacting with the olefin resin (O). In such a case, the olefin-modified acrylic resin (GP) is obtained in the form of a mixture of the olefin resin (O) and the unreacted acrylic resin (A). This mixture may be used as the resin composition (B), or the olefin resin (O) and the unreacted acrylic resin (A) may be used as the acrylic resin (NA). Furthermore, an acrylic resin (NA) or an organic solvent may be added to the mixture as necessary.
For example, when producing an olefin-modified acrylic resin (GP) by production method 1 (post-addition method), the olefin resin (O) and the unreacted acrylic resin (A) are mixed with an acid anhydride-modified olefin resin ( It is an acrylic resin (A1) having a terminal hydroxyl group derived from the (MA) component, in which the hydroxyl group is left unesterified in the acid anhydride of Oa).
When producing an olefin-modified acrylic resin (GP) by production method 2 (pre-addition method), the olefin resin (O) and the unreacted acrylic resin (A) are polymerized only by (meth)acrylic acid-based monomers. It is an acrylic resin (A12) having no terminal hydroxyl group derived from the (MA) component obtained by the above.

Further, in production method 1 (post-addition method) or production method 2 (pre-addition method), the olefin-modified acrylic resin (GP) is obtained in the form of a solution dissolved or dispersed in the reaction solvent used for the reaction. This solution may be used as the resin composition (B), and the reaction solvent may be the organic solvent in the resin composition (B). Furthermore, if necessary, the solution may be diluted with an organic solvent, or an acrylic resin (NA) may be added to the solution.

<Paint composition>
The coating composition (C) of the present invention contains the above resin composition (B) of the present invention.
By including the resin composition (B) in the coating composition (C), adhesion to plastic substrates and compatibility with various resins added as adhesion imparting agents are improved.

Although the resin composition (B) of the present invention may be used as it is for the coating composition (C) of the present invention, optional components may be added to the resin composition (B) as necessary.
Optional components include, for example, paint additives such as brightening agents, fillers, plasticizers, pigment dispersants, thickeners, defoaming agents, and leveling agents; softening agents such as polyurethane; Adhesion imparting agents such as chlorinated polyolefins and maleic anhydride-modified chlorinated polyolefins for the purpose of improving adhesion: and the like.
These may be used individually by 1 type, and may use 2 or more types together.

<Painted object>
The coated article (D) of the present invention has a coating film formed from the resin composition (B) or coating composition (C) of the present invention on the surface of a plastic substrate. That is, the coated article of the present invention is a laminate in which a coating film derived from (B) or the coating composition (C) of the present invention is laminated on a plastic substrate.
The coated article (D) can improve the design and compensate for the drawbacks of the olefin resin such as oil resistance and scratch resistance, so that the resin composition (B) or the coating composition ( A coating film derived from C) is preferably formed, and more preferably a coating film derived from the coating composition (C) is formed on the surface of the polyolefin base material.
Specific examples of plastics constituting the plastic substrate include polyolefin resins such as polypropylene and polyethylene; polycarbonate resins; acrylic resins such as polymethyl methacrylate; ABS (acrylonitrile-butadiene-styrene) resins.

The resin composition (B) and coating composition (C) of the present invention are particularly suitable when the plastic substrate is a polyolefin substrate. Conventionally, it was difficult to form a coating film with good adhesion on such a polyolefin substrate, but by using the resin composition (B) and the coating composition (C) of the present invention, adhesion A coating film with good properties can be formed.

The resin composition (B) and coating composition (C) of the present invention are suitable for coating plastic substrates. Base material: glass, slate plate, concrete, calcium silicate and other silicate base materials; gypsum, asbestos, ceramic and other inorganic base materials; wood, paper, fiber, FRP and other base materials may apply.

As a method for laminating a coating film on a plastic substrate, conventionally known coating methods can be used, and specific examples thereof include a spray coating method, a brush coating method, a dip coating method, a roll coating method, a flow coating method, and the like. mentioned.

A coating film is formed by drying the resin composition (B) or the coating composition (C) of the present invention coated on a plastic substrate by such a coating method, and a coated article as a laminate is obtained.
The drying temperature and drying time in the drying are not particularly limited, and the composition of the resin composition (B) and the coating composition (C) of the present invention (type and content of resin, type and content of organic solvent, etc.), It can be appropriately selected depending on the type of plastic base material.
Drying can be carried out at room temperature to 200° C., but it is preferable to set the temperature below the heat-resistant temperature of the plastic substrate. The drying time is preferably 1 to 30 minutes, but can be set according to the purpose, such as the evaporation rate of the organic solvent used and the drying conditions.

The number of coating films constituting the coated article may be one or two or more.

EXAMPLES The present invention will be described in more detail below with reference to Examples and Comparative Examples, but the present invention is not limited to these. "Parts" and "%" indicate "mass parts" and "mass%", respectively, unless otherwise specified.

<Manufacturing method 1 (post-addition method)>
(Examples 1 to 19)
A four-necked flask equipped with a heating cooler, a thermometer, a dropping funnel and a stirrer was charged with 40 parts of toluene, and after the internal temperature of the flask was raised to 90 ° C., the amount shown in Tables 1 to 3 (parts ) and mercapto alcohol, and 0.15 part of t-butyl peroxy 2-ethylhexanoate was added dropwise over 3 hours.
Then, after allowing the reaction to proceed for 30 minutes, a mixture of 10 parts of toluene and 0.1 part of t-butylperoxy-2-ethylhexanoate was added, and the temperature was maintained at 90°C for an additional 30 minutes. Esterification was carried out by adding an olefin component, a reaction catalyst and 60 parts of toluene under the conditions shown. The esterification reaction was completed in the reaction time shown in Tables 1 to 3, diluted by adding toluene so that the solid content was 43%, and forcedly cooled to a temperature lower than the softening point of the olefin to modify each olefin. A resin composition (B) containing an acrylic resin (GP) and an acrylic resin (NA) was obtained.
The resin composition (B) thus obtained was evaluated for the presence or absence of gelation, storage stability, and adherence to substrate based on the evaluation methods described below. The results are shown in Tables 1-3.

(Comparative example 1)
In Comparative Example 1, resin composition (B) was produced by performing the same operation as in Example 1 under the conditions shown in Table 4, except that esterification was not performed after adding the olefin component, the reaction catalyst, and toluene. and made various evaluations. Table 4 shows the results.

(Comparative Examples 2-3)
Under the conditions shown in Table 4, the reaction was carried out in the same manner as in Example 1 to produce a resin composition (B), which was subjected to various evaluations. Table 4 shows the results.

<Manufacturing method 2 (pre-addition method)>
(Examples 20-38)
A four-necked flask equipped with a heating cooler, a thermometer, a dropping funnel and a stirrer was charged with 35 parts of toluene and the olefin components shown in Tables 5 to 7, and the internal temperature of the flask was raised to 100°C. The temperature was held for 30 minutes to dissolve the olefin component. After complete dissolution, mercapto alcohol was added in the amounts (parts) shown in Tables 5-7, and esterification was carried out under the conditions shown in Tables 5-7. After the reaction time shown in Tables 5 to 7 has passed, a mixture of the acrylic component in the amount (parts) shown in Tables 5 to 7, 0.45 parts of azobisisobutyronitrile and 15 parts of toluene is added dropwise over 3 hours. bottom.
After proceeding with the reaction for 3 hours, toluene was added to dilute the solid content to 43%, and forced cooling was performed to a temperature lower than the softening point of the olefin to obtain each olefin-modified acrylic resin (GP). and a resin composition (B) containing acrylic resin (NA).
The resulting resin composition (B) was evaluated for gelation, storage stability, and substrate adhesion based on the evaluation methods described below. The results are shown in Tables 5-7.

(Comparative Example 4)
In Comparative Example 4, resin composition (B) was produced in the same manner as in Example 20 under the conditions shown in Table 8, except that no esterification was performed after the addition of mercapto alcohol, and various evaluations were performed. gone. Table 8 shows the results.

(Comparative Examples 5-6)
Under the conditions shown in Table 8, the reaction was carried out in the same manner as in Example 20 to produce a resin composition (B), which was then subjected to various evaluations. Table 8 shows the results.

(Comparative Example 7)
A resin composition (B) was produced in the same manner as in Example 20 under the conditions shown in Table 8, except that hydroxyethyl acrylate was added instead of mercaptoalcohol, and various evaluations were performed. Table 8 shows the results.

<Evaluation>
(Evaluation of gelation)
For each resin composition (B), the presence or absence of gelation was confirmed by visual observation.

(Evaluation of storage stability)
Each resin composition (B) was stored in an indoor storage at 23°C for one week.
Separately, 18 parts of toluene was further added to each resin composition (B) to dilute each resin composition (B) so that the solid content of each resin composition (B) was 40%, and then stored in an indoor storage at 23° C. for 1 week. bottom.
The solution state of each resin composition (B) after storage was visually observed to confirm the presence or absence of separation. Storage stability was judged to be good when no separation was observed at least when the solid content of the resin composition (B) was 43%.

(Evaluation of adhesion to substrate)
For each resin composition (B) having good storage stability, a coating for plastics was prepared by the following procedure, and a laminate was formed using the coating for plastics. Adhesion to substrate was evaluated by the following procedure as coating film performance in the obtained laminate.
The resin composition (B) was diluted with a thinner of toluene/xylene=50/50 (mass ratio) to a Ford cup #4 of 12 seconds to prepare a paint for plastics.
The paint for plastics was spray-coated onto a polypropylene substrate (3 mm-thick plate molded from polypropylene resin TX-1810A manufactured by Japan Polychem Co., Ltd.) so as to give a dry film thickness of 15 μm. After standing for 20 minutes, it was dried by heating at 80° C. for 30 minutes to form a coating film, thereby obtaining a laminate.
The coating film of the obtained laminate was cut in a grid pattern (100 pieces at intervals of 1 mm), and Cellotape (registered trademark) was attached to the coating film, and then Cellotape (registered trademark) was peeled off from the substrate. A peeling test was performed by visually confirming the state of peeling of the coating film, and the adhesion to the substrate was evaluated according to the following evaluation criteria.
O: Peeling of the coating film is not observed.
Δ: The coating film was slightly peeled off.
x: The coating film was peeled off.

Blanks in Tables 1-8 indicate that the component was not included.
"Olefin acryl ratio" in Tables 1 to 8 is the mass ratio of component (O) to component (A). The “amount of maleic anhydride” is the mass ratio (%) of the chemical structure derived from maleic acid to the total mass of the chemical structure derived from the acid anhydride-modified olefin resin (Oa). The "OH amount of the (MA) component" is the ratio (mol) of the chemical structure derived from the hydroxyl group of the mercapto alcohol to 1 mol of the chemical structure derived from the acid anhydride of the acid anhydride-modified olefin resin (Oa).

Each abbreviation in Tables 1 to 8 means the following.
Aurolen 350S: Acid-modified polyolefin manufactured by Nippon Paper Industries Co., Ltd. Aurorene 200S: Acid-modified polyolefin manufactured by Nippon Paper Industries Co., Ltd. Auroren 150S: Acid-modified polyolefin manufactured by Nippon Paper Industries Co., Ltd. Superchron 930S: Nippon Paper Industries Co., Ltd. Company-made acid-modified chlorinated polyolefin Superchron 892LS: Nippon Paper Industries Co., Ltd. acid-modified chlorinated polyolefin F-225P: Toyobo Co., Ltd. acid-modified chlorinated polyolefin Superchron 803MWS: Nippon Paper Industries Co., Ltd. Chlorinated polyolefin BA: Butyl acrylate MMA: Methyl methacrylate BMA: Butyl methacrylate CHMA: Cyclohexyl methacrylate SMA: Stearyl methacrylate MAA: Methacrylic acid HEA: Hydroxyethyl acrylate DEAEMA: Methacrylic acid Diethylaminoethyl Aurorene 350S, Aurorene 200S, Aurorene 150S, Superchron 930S, Superchron 892LS, and F-225P are acid-modified olefin resins with maleic anhydride.

As is clear from the results shown in Tables 1 to 3 and 5 to 7, the resin composition of the present invention did not cause gelation and had excellent storage stability. Moreover, the coating film formed using the resin composition was excellent in adhesion to the substrate.

On the other hand, as is clear from the results shown in Tables 4 and 8, in Comparative Examples 1 and 4, since no esterification was performed, the (O) component and the (A) component were bonded via the sulfur element. Since the olefin-modified acrylic resin having no chemical structure was used, the storage stability was poor, and the substrate adhesion could not be evaluated.
Comparative Examples 2 and 5 used olefin-modified acrylic resins that do not have a chemical structure in which the (O) component and the (A) component are bonded via a sulfur element because the (MA) component was not used. Therefore, the storage stability was poor, and the substrate adhesion could not be evaluated.
Comparative Examples 3 and 6 used olefin-modified acrylic resins that did not have the chemical structure represented by the general formula (1).
In Comparative Example 7, hydroxyethyl acrylate was used in place of the (MA) component, so that when the (meth)acrylic acid-based monomer was polymerized, it formed a bridge structure with nearby olefin molecules, and the acrylic component was added. Gelation occurred in 1.5 hours, the storage stability was poor, and substrate adhesion could not be evaluated.

INDUSTRIAL APPLICABILITY The resin composition of the present invention is excellent in storage stability over a long period of time, and can be directly coated even on difficult-to-paint plastic substrates without pretreatment or primer coating. The coating film has excellent adhesion to the substrate. For this reason, it can be suitably used for polyolefin-based hard-to-adhere materials in various fields such as automotive exterior parts such as bumpers, wheel caps, mudguards, and lamp housings, automotive interior parts such as instrument panels and console boxes, and home appliances. , is of great industrial importance.

Claims (10)

An olefin-modified acrylic resin having a chemical structure represented by the following general formula (1), in which an olefin resin and an acrylic resin are bonded via a sulfur element.

(In formula (1), R ¹¹ and R ¹² each independently represent a hydrogen atom or a chlorine atom, R ²¹ represents a linear or branched C 1-6 alkylene group, R ³¹ , R ³² each independently represents a hydrogen atom or a methyl group, R ⁴¹ and R ⁴² each independently represent a linear or branched chain optionally substituted with a hydrogen atom, a hydroxyl group, an amine group, an alkoxy group or a carbonyl group It represents a chain alkyl group having 1 to 18 carbon atoms, an aliphatic or aromatic ring having 3 to 6 carbon atoms, and each of R ⁵¹ to R ⁵³ independently represents a hydrogen atom or a methyl group.) 2. The olefin-modified acrylic resin according to claim 1, which is a reaction product of the olefin resin and an acrylic resin having terminal hydroxyl groups derived from mercapto alcohol. 2. The olefin-modified acrylic resin according to claim 1, which is a reaction product of an olefin resin having a terminal mercapto group derived from a mercapto alcohol and the acrylic resin. 4. The olefin-modified acrylic resin according to claim 2 or 3, wherein said mercaptoalcohol is mercaptoethanol or mercaptobutanol. The olefin resin is an olefin resin modified with an acid anhydride,
Any one of claims 2 to 4, wherein the chemical structure derived from the hydroxyl group of the mercapto alcohol is 0.6 to 2.5 mol per 1 mol of the acid anhydride-derived chemical structure of the acid anhydride-modified olefin resin. or the olefin-modified acrylic resin according to any one of items. The olefin resin is an olefin resin modified with an acid anhydride,
6. Any one of claims 1 to 5, wherein the mass ratio of the acid anhydride-derived chemical structure to the total mass of the acid anhydride-modified olefin resin-derived chemical structure is 1.7 to 5.0%. The olefin-modified acrylic resin according to the item. The olefin-modified acrylic resin according to claim 5 or 6, wherein the acid anhydride is maleic anhydride. A resin composition comprising the olefin-modified acrylic resin according to any one of claims 1 to 7 and an acrylic resin not bound to an olefin. A coating composition comprising the resin composition according to claim 8 . A coated article comprising a coating film formed from the resin composition according to claim 8 or the coating composition according to claim 9 on the surface of a plastic substrate.