KR20120056974A - Acrylic laminate films and method for fabricating the same - Google Patents

Abstract

PURPOSE: A manufacturing method of an acryl-based laminate film is provided to provide an acryl-based laminate film having improved blushing resistance and coatability together with excellent weatherability, moldability, transparence, thereby preventing the transparency of an acrylic laminate film. CONSTITUTION: A manufacturing method of an acryl-based laminate film comprises a step of manufacturing a granular acrylic rubber copolymer consisting of a core and a shell; a step of manufacturing a bead- phase acrylic thermoplastic resin; and a step of melt-extruding a composition which is a mixture of the granular acrylic rubber copolymer, and the bead- phase acrylic thermoplastic resin. The acrylic rubber copolymer comprises 30-50 weight% of the core and 50-70 weight% of the shell.

Description

Acrylic laminate film and its manufacturing method {Acrylic laminate films and method for fabricating the same}

The present invention relates to an acrylic laminate film containing an acrylic resin composition excellent in stress whitening resistance, transparency, impact resistance, film forming property, and processability.

Acrylic resins have excellent transparency, weather resistance, and excellent molding, and are widely used in various industries including optical products and electronics housings. In particular, the present invention may be applied by molding into a sheet or a film or by laminating plastics, wood, and metals. The film formed of such an acrylic resin may have a high film formability and impact resistance at the time of processing, and a transparency may not be lowered, thereby making it easy to change thickness and produce a film having excellent film forming property. To this end, a method of dispersing a component consisting of an acrylic rubber in an acrylic resin or using a graft copolymer itself has been widely devised. Japanese Patent Application Laid-open No. Hei 10-306192 discloses a film made of a resin composition containing an acrylic polymer having a specific reduced viscosity and a multilayer structured acrylic polymer as a film having an easy thickness control. The acrylic polymer is manufactured in a multi-layered structure by changing the composition step by step in order to reduce the transparency or whitening phenomenon, but the impact resistance is poor, there is a problem that the transparency of the secondary processed film after the lamination process and stress whitening occurs .

The present invention is to solve the problems of the prior art, using an acrylic rubber copolymer consisting of a multi-layer structure of the inner layer and the outer layer, the acrylic thermoplastic resin has the same composition as the outer layer to increase the compatibility, transparency and In addition to implementing stress whitening resistance, an object of the present invention is to produce an acrylic laminate film capable of improving impact resistance and film formation.

In addition, it is an object to prevent the deterioration of optical properties by controlling the content of the acrylic rubber copolymer composed of a multi-layer structure.

As a result of efforts to solve the above problems, the present inventors formed an acrylic rubber copolymer in a multilayer structure of the inner layer / outer layer (core / shell), the average particle diameter is manufactured to 50 ~ 150nm, The outer layer (shell) is the same as the monomer composition of the acrylic thermoplastic resin composition to suppress the turbidity or change in the transparency when the deformation, the acrylic rubber laminate to improve the impact resistance without inhibiting optical properties by controlling the content of the acrylic rubber copolymer and The manufacturing method can be provided.

EMBODIMENT OF THE INVENTION Hereinafter, this invention is demonstrated concretely.

Method for producing an acrylic laminate film according to the present invention

(A) (a1) mixing a methacrylic acid ester monomer, an aromatic vinyl monomer, a crosslinking agent, and an initiator with ion-exchanged water in a reactor in a nitrogen atmosphere, followed by emulsion polymerization to prepare an inner layer portion; And (a2) adding an acrylic ester monomer, a methacrylic acid ester monomer, a chain transfer agent, an initiator and a crosslinking agent to an reactor including the inner layer prepared in (a1) to form an outer layer (shell) by emulsion polymerization and then aggregate, Dehydration and drying to prepare a particulate acrylic rubber copolymer;

(B) Suspension polymerization reaction is carried out by adding an acrylic acid ester monomer, a methacrylic acid ester monomer, a chain transfer agent, and an initiator to a solution obtained by mixing a dispersant and a buffer salt with ion-exchanged water, followed by washing, dehydration and drying to form a bead-type acrylic thermoplastic resin. Manufacturing step; And

(C) melt extrusion molding the composition of the particulate acrylic rubber copolymer and the bead-shaped acrylic thermoplastic resin.

The acrylic rubber copolymer of (A) is characterized in that the inner layer part is 30 to 50% by weight, the outer layer part is 50 to 70% by weight. When the weight ratio of the inner layer portion and the outer layer portion is out of the mixed weight ratio, the impact resistance is lowered, and thus, the intended shock expression is difficult to occur.

In addition, it is preferable that the inner layer part of the said (A) acrylic rubber copolymer is 50-90 weight% of methacrylic acid ester monomers, and 10-50 weight% of aromatic vinylic monomers with respect to the total monomer used. In addition, it is preferable that the outer layer part of the said (A) acrylic rubber copolymer is 10-50 weight% of an acrylic ester monomer and 50-90 weight% of a methacrylic ester monomer with respect to the total monomer used. In this case, when the acrylic ester monomer is less than 10%, transparency and physical properties may be lowered due to compatibility with the thermoplastic resin, and in the case of 50% or more, the polymerization conversion may be lowered.

At this time, it is preferable that the average particle diameter of the said acrylic rubber copolymer is 50-150 nm. If the average particle diameter is less than 50nm, the impact resistance is not reduced because the shock is not expressed, and the surface haze generation and whitening resistance is difficult to implement at 150nm or more.

When the temperature of the ion-exchanged water reaches 50 to 70 ° C. under a nitrogen atmosphere in the step of preparing the inner layer part (a1), the mixture is sufficiently stirred by adding an emulsifier and then methacrylic acid ester monomer, aromatic vinyl monomer, and methacrylic acid. , A solution in which any one or more comonomers selected from acrylic acid, a crosslinking agent, and an initiator are mixed is added to a reactor for emulsion polymerization. At this time, in order to express the impact resistance, the content of the acrylic monomers relative to the total monomers is preferably 30 to 50% by weight, and when the content is less than the shock expression is difficult.

In the step of preparing the outer layer part (a2), a methacrylic acid ester monomer and an acrylic acid ester monomer, a chain transfer agent, an initiator, and a crosslinking agent are added to the reactor including the inner layer part prepared in (a1) so as to express stress whitening resistance. Emulsion polymerization is carried out to form an outer layer covering the inner layer. At this time, it is preferable to add while reducing the content of the acrylic ester monomer step by step in the methacrylic ester monomer and acrylic ester monomer in the reactor. That is, in using 50 to 90% by weight of methacrylic acid ester monomer and 10 to 50% by weight of acrylic ester monomer relative to the total monomers, it is preferable to divide the process into at least two or more stages and to add the reactor to the reactor. desirable. At this time, the monomer content of the acrylic acid ester is preferably to decrease the content every time. It is difficult to express stress whitening resistance when mixed with the acrylic thermoplastic resin unless the content of the acrylic ester monomer in the outer layer is reduced.

The acrylic ester monomer is an acrylic acid acrylate having 1 to 15 carbon atoms, more preferably selected from ethyl acrylate, n-butyl acrylate, t-butyl acrylate and 2-ethylhexyl acrylate having 2 to 8 carbon atoms. It includes either monomer.

The methacrylic acid ester monomer is a methacrylic acid ester having 1 to 15 carbon atoms, preferably methyl methacrylate, ethyl methacrylate, n-butyl methacrylate, I-butyl methacrylate, t-butyl meth It includes any one monomer selected from acrylate, lauryl methacrylate, 2-ethylhexyl methacrylate.

The aromatic vinyl monomer includes one or more selected from the group consisting of styrene, α-methylstyrene, ο-ethylstyrene, p-ethylstyrene, vinyltoluene, and derivatives thereof.

The emulsifier is an anionic emulsifier such as alkaline alkyl phosphate having 4 to 30 carbon atoms and alkyl sulfate salt such as sodium dodecyl sulfate, sodium dodecylbenzene sulfate, and 0.1 to 5 parts by weight based on 100 parts by weight of the total monomers.

The crosslinking agent is 1,2-ethanedioldi (meth) acrylate, 1,3-propanedioldi (meth) acrylate, 1,4-butanedioldi (meth) acrylate, 1,5-pentanedioldi (meth ) Acrylate, 1,6-hexanediol di (meth) acrylate, divinylbenzene, ethylene glycol di (meth) acrylate, propylene glycol di (meth) acrylate, butylene glycol di (meth) acrylate, tri At least one selected from ethylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, polypropylene glycol di (meth) acrylate, polybutylene glycol di (meth) acrylate or allyl (meth) acrylate The amount used is 0.1 to 10 parts by weight based on 100 parts by weight of the total monomers.

In addition, the inner layer portion of the (a1) may further comprise 0.1 to 10 parts by weight of the graft agent based on 100 parts by weight of the total monomers. In this case, the graft agent includes at least one monomer selected from allyl (meth) acrylate or diallyl maleate.

The initiator is cumene hydroperoxide, diisopropyl benzene hydroperoxide, azobis isobutylonitrile, tertiary butyl hydroperoxide in the presence of ferrous sulfate, sodium ethylenediaminetetraacetate, sodium formaldehyde sulfoxylate, It is one or more selected from paramethane hydroperoxide and benzoyl peroxide, and it is preferable to use less than 10 parts by weight based on 100 parts by weight of the total monomers.

In addition, the chain transfer agent for molecular weight adjustment may be used an alkyl mercaptan having 2 to 18 carbon atoms, benzyl mercaptan, mercaptoic acid and the like, preferably an alkyl mercaptan having 4 to 12 carbon atoms.

It is preferable to use 100-500 weight part of ion-exchange water with respect to 100 weight part of all monomers.

When the polymerization reaction is completed in the step (A), the resin composition and water are separated and recovered through the coagulation, washing and drying process using a coagulant. At this time, the flocculant to be used is an aqueous organic acid salt solution, for example, sodium acetate, calcium acetate, sodium formate, calcium formate and the like can be used. The amount of the organic acid salt used is 0.01 to 5 parts by weight relative to the total suspension polymerization solution, more preferably 0.01 to 1 part by weight.

The monomer composition of the acrylic thermoplastic resin in step (B) is preferably the same as the monomer composition of the outer layer portion of the acrylic rubber copolymer. If the composition is inconsistent, the compatibility between the acrylic rubber copolymer and the acrylic thermoplastic resin is poor, the optical properties and transparency are lowered, and when the acrylic rubber copolymer and the acrylic thermoplastic resin are mixed, it is difficult to mix at least 30% by weight of the acrylic rubber copolymer. .

In addition, as a dispersing agent, the copolymer of acrylic acid and methacrylic acid ester, its salt, polyvinyl alcohol, etc. are used. The preferred amount is 0.1 to 2% by weight relative to the total monomer in the aqueous solution, a small amount of inorganic salt may be used as a dispersing aid.

The suspension polymerization reaction of (B) is carried out in a nitrogen atmosphere at a stirring speed of 500 to 700 rpm for a sufficient time at a temperature between 60 and 110 ° C., and when the reaction is completed, washing and drying the beads to have impact resistance. An acrylic thermoplastic resin is obtained.

In the present invention, the mixed weight portion of the acrylic rubber copolymer of step (C) and the acrylic thermoplastic resin is an important parameter in stress whitening resistance and impact resistance, and the acrylic rubber copolymer is 30 to 60% by weight, more preferably 40 to It is characterized by being 50% by weight. In this case, when the content of the acrylic rubber copolymer is less than 30% by weight, the impact resistance is weakened and can be easily broken during processing.It is difficult to achieve stress whitening resistance, and when it exceeds 60% by weight, the impact resistance is improved, but the transparency and optical properties are improved. It's hard to see. In addition, the acrylic thermoplastic resin (B) is 70 to 40% by weight, more preferably 60 to 50% by weight when mixed with the acrylic rubber copolymer (A).

The resin composition according to the present invention may comprise common thermoplastic additives such as fillers, reinforcing agents, colorants, lubricants, stabilizers, antioxidants, heat resistant and ultraviolet stabilizers and other compound components. In particular, it is preferable to add a ultraviolet absorbent to impart weather resistance. 300 or more are preferable and, as for the molecular weight of a ultraviolet absorber, 400 or more are more preferable. If the ultraviolet absorber having a molecular weight of 300 or more is used, mold contamination due to volatilization of the ultraviolet absorber can be prevented when vacuum molding in the injection molding mold. Although the kind of ultraviolet absorber is not specifically limited, A benzotriazole type or a triazine type can be used preferably.

As the molding method of the acrylic laminate film of the present invention, a melt casting method, a T-die method, a calender method, or the like can be used, and a T-die method is preferable.

Although the thickness of the said acrylic laminate film is not specifically limited, 300 micrometers or less are preferable and 50-300 micrometers are more preferable.

The composition mixed with the acrylic rubber copolymer and the acrylic thermoplastic resin according to the present invention can be manufactured into a molded article by a method such as injection and extrusion, and specifically, an acrylic laminate having stress whitening resistance and impact resistance and not impairing transparency. Films can be produced.

As described above, the manufacturing method of the acrylic laminate film according to the present invention is excellent in weather resistance, moldability, transparency, stress whitening resistance, film forming properties can be improved to prevent whitening phenomenon during processing, transparency is not lowered Acrylic laminate film can be produced. In particular, by minimizing the content of the acrylic rubber copolymer to prevent deterioration of the optical properties, and composed of a multi-layer structure of the inner layer / outer layer, and by polymerizing the outer layer in at least two stages and has a stress whitening resistance acrylic acrylic polymer (B) is acrylic By improving the compatibility by making the composition and the composition corresponding to the outer layer (shell) of the rubber copolymer in the same manner, there is an advantage that can realize the acrylic white film to achieve the stress whitening resistance and improved transparency and optical properties.

Hereinafter, the present invention will be described with reference to preferred examples, but the present invention is not limited to the following examples.

(Example)

In the step (A) according to the invention to prepare an acrylic rubber copolymer was carried out as follows. First, 250 parts of ion-exchanged water, 0.002 parts of ferrous sulfate, 0.008 parts of EDTA-2Na salt, 0.2 parts of sodium formaldehyde sulfoxylate, and 2 parts of sodium dodecyl sulfate were introduced into a reactor with a stirrer, and after nitrogen replacement, the temperature was raised to 65 ° C. It was. After heating, 33% by weight of butyl methacrylate, 7% by weight of styrene, 1% by weight of allyl methacrylate, and 0.05 parts of cumene hydroperoxide were added dropwise for 30 minutes, followed by 90 minutes After dropwise addition, the mixture was stirred for 1 hour, followed by emulsion polymerization. The average particle diameter of the glassy polymer obtained at this time was 40 nm.

Next, 0.5 parts of sodium dodecyl sulfate, 6% by weight of butyl acrylate, 24% by weight of methyl methacrylate, 0.3% by weight of allyl methacrylate, 0.04 parts of dodecyl mercaptan, and cumene hydroperoxide in the obtained polymer. After adding the auxiliary mixed solution dropwise over 1 hour, 3% by weight of butyl acrylate, 27% by weight of methyl methacrylate, 0.09 parts of dodecyl mercaptan, and 0.05 parts of cumene hydroperoxide were added dropwise over 1 hour. The polymerization was carried out for 1 hour. The average particle size of the final polymer was 60 nm. In order to agglomerate the acrylic rubber copolymer as the final polymer, 0.02% by weight of calcium acetate relative to the solid particles was added to aggregate at 70 ° C, and the obtained particle powder was dehydrated in distilled water and then dried at 80 ° C.

In the step (B), the acrylic thermoplastic resin was prepared by adding 85% by weight of methyl methacrylate, 15% by weight of butyl acrylate, 0.3 part of dodecyl mercaptan, and 0.15 part of azobisisobutyronitrile, followed by ion exchange. 0.12 g of 70% methacrylic acid and 30% methyl methacrylate copolymer substituted with sodium as a dispersant in 250 parts of water, and as a buffer salt, 1.2 g of NaH ₂ PO ₄ ˜2H ₂ O, Na ₂ HPO ₄ ˜12H ₂ 1.8 g of O was added to the dissolved solution, and the mixture was subjected to a first polymerization reaction at 80 ° C. for 90 minutes under stirring at 600 rpm. A polymerization peak occurred and the temperature was raised to 110 ° C. for 30 minutes. It was then cooled to 30 ° C. The bead polymer obtained by the reaction was washed and dehydrated three times with distilled water, and the bead acrylic thermoplastic resin was dried in an oven.

An acrylic laminate film composition was prepared by mixing 40% by weight of the acrylic rubber copolymer particle powder and the bead-shaped acrylic thermoplastic resin (B) at 60% by weight after the steps (1) and (2).

(Example 2)

An acrylic laminate film composition was prepared in the same manner as in Example 1, except that the core of the acrylic rubber copolymer contained 50 wt%.

(Example 3)

The composition of the outer shell portion of the acrylic rubber copolymer was polymerized with 4.5% by weight of butyl acrylate and 25.5% by weight of methyl methacrylate, and the acrylic thermoplastic resin was made into 87.5% by weight of methyl methacrylate and 12.5% by weight of butyl acrylate. An acrylic laminate film composition was manufactured in the same manner as in Example 1, except that the mixture was polymerized and mixed.

(Comparative Example 1)

In the same manner as in Example 1, except that the polymerization of the acrylic thermoplastic resin of step (B) by methyl methacrylate 95% by weight, but 5% by weight of butyl acrylate in the same process as in Example 1 acrylic laminate A film composition was prepared.

(Comparative Example 2)

In the same manner as in Example 1, except that the polymerization of the acrylic thermoplastic resin of step (B) by methyl methacrylate 85% by weight, 15% by weight of methyl acrylate in the same process as in Example 1 acrylic laminate A film composition was prepared.

(Comparative Example 3)

When preparing the acrylic rubber copolymer of step (A) in the same manner as in Example 1, the part corresponding to the outer layer (shell) is divided into two steps without polymerization of 6% by weight of butyl acrylate, 54% by weight of methyl methacrylate An acrylic laminate film composition was manufactured in the same manner as in Example 1, except that polymerization was carried out by adding the same.

(Comparative Example 4)

Polymerized in the same manner as in Example 1, but in the same process as in Example 1 except mixing 20% by weight of the acrylic rubber copolymer (A) and 80% by weight of the acrylic thermoplastic resin in the acrylic laminate film composition Was prepared.

Compositions obtained in Examples and Comparative Examples were prepared by using an extruder by mixing 1.5% by weight of tinubin 234 with an ultraviolet absorber to 100 parts by weight of the polymer for physical property evaluation test. This was molded at 260 ° C. with a T-die extruder to obtain a 70 micrometer thick film sample, and then subjected to the following evaluation method to show the results in Table 1.

(evaluation)

 Graft rate (G): After dissolving the powder prepared in step (A) in acetone (Acetone), and separated into an insoluble fraction and a soluble fraction, the insoluble fraction was determined as a graft powder.

G = (weight of insoluble-weight of rubber polymer) / weight of rubber polymer X 100

 Transparency (%) and haze (Haze): measured by Hazemeter according to ASTM D1003 method

 Yellow Index (YI): ASTM D1925 Method

 Tensile strength: measured at room temperature using a Zwick / Roell UTM (Universal testing machine, model Z010). Specimens were prepared with a width of 10 mm and measured at a tensile rate of 50 mm / minute.

 Average particle size (nm): measured by light scattering method according to ASTM D1705 and ASTM D2921

 Pencil Hardness: Measured at 1 kg load according to ASTM D3363

 Stress whitening: Fold the film 180 degrees at room temperature and observe the whitening state.

(Circle): Whitening is not recognized.

(Triangle | delta): A little whitening is recognized.

X: Whitening is remarkable.

As can be seen from the results of Table 1, it was confirmed that the acrylic laminate film according to the present invention is not stress whitening, does not impair transparency after processing the film, and can be used as a laminate film with excellent impact resistance and workability. .

In the present invention as described above has been described by specific matters and limited embodiments, but this is provided only to help a more general understanding of the present invention, the present invention is not limited to the above embodiments, the present invention belongs to Many modifications and variations are possible in the art to those skilled in the art.

Accordingly, the spirit of the present invention should not be limited to the described embodiments, and all of the equivalents and equivalents of the claims, as well as the following claims, will fall within the scope of the present invention. .

Claims (14)

(A) (a1) mixing a methacrylic acid ester monomer, an aromatic vinyl monomer, a crosslinking agent, and an initiator with ion-exchanged water in a reactor in a nitrogen atmosphere, followed by emulsion polymerization to prepare an inner layer portion; And (a2) adding an acrylic ester monomer, a methacrylic acid ester monomer, a chain transfer agent, an initiator and a crosslinking agent to an reactor including the inner layer prepared in (a1) to form an outer layer (shell) by emulsion polymerization and then aggregate, Dehydration and drying to prepare a particulate acrylic rubber copolymer;
(B) Suspension polymerization reaction is carried out by adding an acrylic acid ester monomer, a methacrylic acid ester monomer, a chain transfer agent, and an initiator to a solution obtained by mixing a dispersant and a buffer salt with ion-exchanged water, followed by washing, dehydration and drying to form a bead-type acrylic thermoplastic resin. Manufacturing step; And
(C) melt-extrusion molding the composition of the particulate acrylic rubber copolymer and the bead-shaped acrylic thermoplastic resin; acrylic laminate film manufacturing method comprising a. The method of claim 1,
The acrylic rubber copolymer of the above (A) is 30 to 50% by weight of the inner layer portion, 50 to 70% by weight of the outer layer portion of the acrylic laminate film production method. The method according to claim 1 or 2,
The inner layer portion of the acrylic rubber copolymer (A) is 50 to 90% by weight of the methacrylic acid ester monomer and 10 to 50% by weight of the aromatic vinyl monomer relative to the total monomers used. The method according to claim 1 or 2,
The outer layer portion of the (A) acrylic rubber copolymer is an acrylic laminate film production method of 10 to 50% by weight acrylic acid ester monomer and 50 to 90% by weight methacrylic acid ester monomer relative to the total monomers used. The method of claim 1,
The acrylic thermoplastic resin (B) is a method of manufacturing an acrylic laminate film, characterized in that the same composition as the outer layer portion of the (A) acrylic rubber copolymer. The method of claim 1,
The mixing weight ratio of the particulate acrylic rubber copolymer and the bead-shaped acrylic thermoplastic resin in the step (C) is 30 ~ 60: 70 ~ 40 acrylic laminate film manufacturing method. The method of claim 1,
The average particle diameter of the said particulate acrylic rubber copolymer of (A) is 50-150 nm, The acrylic laminated film manufacturing method. The method of claim 1,
The aromatic vinyl monomer is at least one selected from the group consisting of styrene, α-methyl styrene, ο-ethyl styrene, p-ethyl styrene, vinyl toluene, and derivatives thereof. The method of claim 1,
The crosslinking agent is 1,2-ethanedioldi (meth) acrylate, 1,3-propanedioldi (meth) acrylate, 1,4-butanedioldi (meth) acrylate, 1,5-pentanedioldi (meth ) Acrylate, 1,6-hexanediol di (meth) acrylate, divinylbenzene, ethylene glycol di (meth) acrylate, propylene glycol di (meth) acrylate, butylene glycol di (meth) acrylate, tri At least one selected from ethylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, polypropylene glycol di (meth) acrylate, polybutylene glycol di (meth) acrylate or allyl (meth) acrylate Acrylic laminate film production method. The method of claim 1,
The inner layer portion of the acrylic laminate film manufacturing method further comprises 0.1 to 10 parts by weight of the graft agent based on 100 parts by weight of the total monomers. The method of claim 10,
The graft agent is an acrylic laminate film manufacturing method comprising at least one monomer selected from allyl (meth) acrylate or diallyl maleate. The method of claim 1,
The initiator is at least one selected from cumene hydro peroxide, diisopropyl benzene hydroperoxide, azobis isobutylonitrile, tertiary butyl hydroperoxide, paramethane hydroperoxide, benzoyl peroxide. The method of claim 1,
The emulsifier is an acrylic laminate film manufacturing method comprising an alkyl alkyl phosphate or alkyl sulfate salt of 4 to 30 carbon atoms. An acrylic laminate film made of any one of claims 1 to 13.