JPH1045854A - Multilayer polymer having improved weather resistance and acrylic resin film comprising the multilayer polymer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an acrylic multi-layer suitable for use in protective films and sheets having excellent transparency and stress whitening property in which a light stabilizer does not bleed out or volatilize during molding and kneading, and improved weather resistance. To provide a structural polymer and an acrylic resin film comprising the multilayer structural polymer. SOLUTION: The innermost layer polymer (A), the second layer polymer (B), the outermost layer polymer (C) in which a specific monomer is copolymerized, and the amount of the alkyl acrylate polymer (B) From at least one interlayer polymer (D) monotonically decreasing toward the polymer (C),
(A), (B), (D),
(C) A multilayer polymer having a multilayer structure and improved gel stability having a gel content of at least 50% by weight or more, and an acrylic resin film comprising the multilayer polymer in the order of (C).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an acrylic multi-layer polymer having excellent clarity and stress whitening property, an improved weather resistance and a low bleed-out of an additive suitable for use in a sheet and an acrylic polymer. The present invention relates to an acrylic resin film composed of a multilayer polymer.

[0002]

2. Description of the Related Art Acrylic resins, especially methyl methacrylate polymers, have been used as molding materials in various fields because of their beautiful appearance. However, since it is hard and brittle, the elasticity is insufficient when used for special applications such as protective films and sheets.
An acrylic multi-layer structure polymer having an elastic polymer as described in JP-A-140161 and JP-B-59-36646 has been proposed. In addition, these acrylic multi-layer polymers are kneaded with a light stabilizer to provide light stability,
It is used as a protective film or sheet for imparting weather resistance.

[0003]

The multilayer polymer having improved light stability and weather resistance by kneading a light stabilizer can knead various light stabilizers, and its production method is simple. But,
It is said that the light stabilizer partially bleeds out and volatilizes during molding and kneading, causing stains on molds and rolls, and that if used for a long time, the light stabilizer bleeds out and the weather resistance of the polymer decreases. There is a problem.

SUMMARY OF THE INVENTION It is an object of the present invention to provide an acrylic multi-layer structure suitable for use as a protective film or sheet which is excellent in transparency and stress whitening property in which the light stabilizer does not bleed out or volatilize during molding and kneading, and has improved weather resistance. An object of the present invention is to provide a polymer and an acrylic resin film comprising the multilayer structure polymer.

[0005]

Means for Solving the Problems In order to solve these problems, the present inventors have conducted intensive studies on chemically bonding a light stabilizer to a multilayer polymer, and as a result, have found that reactive light It has been found that a method of copolymerizing a 2,2,6,6-tetramethylpiperidine monomer, which is a stabilizer, into a multilayer polymer most effectively improves stains and weather resistance of molds and rolls.

The gist of the present invention is as follows: 5 to 35 parts by weight of an innermost layer polymer (A), 10 to 50 parts by weight of a second layer polymer (B), and 30 to 80 parts by weight of an outermost layer weight. Coalescence (C),
And 5 to 35 parts by weight of at least one interlayer polymer (D) such that the amount of alkyl acrylate monotonically decreases from the polymer (B) toward the polymer (C),
Each of the polymers is polymerized in the order of (A), (B), (D), and (C), and has a gel content of at least 50% by weight or more, and has improved weather resistance and a multilayer structure. And an acrylic resin film comprising the multilayer polymer and the multilayer structure polymer.

(A) 80 to 100% by weight of carbon number 1 to 8
Alkyl acrylate having an alkyl group or alkyl methacrylate having an alkyl group having 1 to 4 carbon atoms (A1), 0 to 20% by weight of a monomer having a copolymerizable double bond (A2), 0 to 10% by weight % Of the polyfunctional monomer (A3), and 0.1 to 5 parts by weight of the innermost layer polymer (A) having a composition of 0.1 to 5 parts by weight with respect to 100 parts by weight of the total amount of (A1) to (A3). ).

(B) 80 to 100% by weight of carbon number 1 to 8
An alkyl acrylate (B1) having an alkyl group of
0 to 20% by weight of a monomer having a copolymerizable double bond (B2), 0 to 10% by weight of a polyfunctional monomer (B3),
And a second layer polymer (B) having a composition of 0.1 to 5 parts by weight of a graft crosslinking agent based on 100 parts by weight of the total amount of (B1) to (B3).

(C) 51 to 100% by weight of carbon number 1 to 4
Alkyl methacrylate having an alkyl group of the formula (C
1) a total amount of 0 to 49% by weight of a monomer (C2) having a copolymerizable double bond, and (C1) and (C2)
An outermost polymer having a glass transition temperature of at least 50 ° C or more, comprising 0.01 to 10 parts by weight of 2,2,6,6-tetramethylpiperidine monomer having the structure shown below based on 00 parts by weight (C).

[0010]

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(D) an alkyl acrylate (D1) having 10 to 90% by weight of an alkyl group having 1 to 8 carbon atoms;
0 to 90% by weight of an alkyl methacrylate having an alkyl group having 1 to 4 carbon atoms (D2), 0 to 20% by weight of a monomer having a copolymerizable double bond (D3), 0 to 10% by weight of Polyfunctional monomers (D4), and (D1)-(D
The second layer polymer (B) comprises a composition of 0.1 to 5 parts by weight of the graft-linking agent based on 100 parts by weight of the total amount of 4).
And an intermediate layer polymer (D) comprising at least one layer between the polymer and the outermost layer polymer (C).

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION The innermost layer polymer (A) of the present invention comprises 8
0 to 100% by weight of an alkyl acrylate and an alkyl methacrylate (A1), 0 to 20% by weight of a monomer having a copolymerizable double bond (A2), and 0 to 10% by weight.
It can be used in the range of the weight-% polyfunctional monomer (A3) depending on the desired physical properties.

The alkyl acrylate and alkyl methacrylate (A1) constituting the polymer (A) of the present invention
As an alkyl acrylate having an alkyl group having 1 to 8 carbon atoms; for example, methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, octyl acrylate, and the like; and an alkyl group having 1 to 4 carbon atoms. Having alkyl methacrylate; for example, methyl methacrylate, ethyl methacrylate, propyl methacrylate,
Butyl methacrylate and the like can be mentioned, and the alkyl acrylate and the alkyl methacrylate can be used as one kind or as a mixture of two or more kinds. Since the polymer (A) also has a role of acting as an elastic body, the Tg is preferably low, and the main component (A1) is preferably butyl acrylate or a mixture of butyl acrylate and methyl or ethyl methacrylate. It is most preferable that the alkyl acrylate and alkyl methacrylate (A1) are used in a unified manner in the polymer of each layer to be subsequently polymerized. However, depending on the final purpose, two or more monomers may be used, May be used.

As the monomer (A2) having a copolymerizable double bond according to the present invention, alkyl (meth) acrylate,
Acrylic monomers such as alkoxy (meth) acrylate, cyanoethyl (meth) acrylate, (meth) acrylic acid and acrylamide; styrenes such as styrene and 4-methylstyrene; and other (meth) acrylonitrile. The monomers can be used as one kind or as a mixture of two or more kinds. Further, in order to make the overall refractive index close and improve the transparency, it is preferable to add in an amount not exceeding 20% by weight.

As the polyfunctional monomer (A3) in the present invention, ethylene glycol dimethacrylate, 1,3-
Butylene glycol dimethacrylate, glycerol dimethacrylate, 1,6-hexanediol dimethacrylate, 1,4-butylene diol dimethacrylate,
Dimethacrylates such as propylene dimethacrylate are preferred, and divinylbenzene, alkylene glycol diacrylate and the like may be used. The polyfunctional monomer can be used as one kind or a mixture of two or more kinds for effective crosslinking. In order to improve the physical properties of the elastic body, it is preferable to add (A3) in a range not exceeding 10% by weight. If (A3) is more than 10% by weight, the crosslinking density is increased and the stress whitening property is lowered, which is not preferred.

Further, (A2) and (A3) are not always necessary depending on the amount and use of the graft crossing agent.

The total amount of (A1) to (A3) is 100
0.1 to 5 parts by weight of the graft crosslinking agent is used per part by weight.

As the graft-linking agent in the present invention, allyl, methacryl, or crotyl ester of copolymerizable α, β-unsaturated (di) carboxylic acid, or allyl of acrylic acid, methacrylic acid, maleic acid, or fumaric acid is used. Esters are mentioned. Preferably, allyl esters, particularly allyl methacrylate, exhibit excellent effects.
In addition, the graft-linking agent can be used as one kind or a mixture of two or more kinds depending on the purpose. The amount of the graft-linking agent is important, and the (B), (D), (D) At least 0.1 part by weight is required for grafting with C), and if it exceeds 5 parts by weight, stress whitening property is deteriorated.

The 2,2,6,6-tetramethylpiperidine monomer (hereinafter abbreviated as TMPM) described below can sufficiently improve the weather resistance in the polymer (A) by 10 parts by weight or less. If the content of TMPM in the multilayer structure polymer is sufficient to impart weather resistance, the polymer (A) is not necessarily required. Further, the amount is preferably 0.01 to 5 parts by weight in order to have less influence on the multilayer structure polymer of the present invention and obtain more sufficient weather resistance.

The content of the polymer (A) in the multilayer polymer of the present invention is 5 to 35 parts by weight, preferably 5 to 35 parts by weight.
To 15 parts by weight, especially when synthesizing the multi-layered polymer by emulsion polymerization.
A range of １５15 parts by weight is preferred.

Next, the second layer polymer (B) in the present invention
Is an alkyl acrylate (B1) having an alkyl group having 1 to 8 carbon atoms of 80 to 100% by weight, a monomer (B2) having a copolymerizable double bond of 0 to 20% by weight,
The polyfunctional monomer (B3) in an amount of 0% by weight can be used according to the desired physical properties.

In the present invention, the alkyl acrylate (B
Examples of 1) include the same alkyl acrylates having an alkyl group having 1 to 8 carbon atoms as in (A1). Particularly, since the polymer (B) is an elastic body, it is better that the glass transition temperature is low, and the main component (B1) is preferably butyl acrylate.

As the monomer (B2) in the present invention, those similar to (A2) can be mentioned. (B2) is preferably added in an amount not exceeding 20% by weight in order to make the overall refractive index close and improve transparency, and the polymer (C)
The same alkyl methacrylate as (C1) as the main component in the above is preferable, and methyl methacrylate is particularly preferable because of excellent transparency.

As the monomer (B3) in the present invention, those similar to (A3) can be mentioned. In order to improve the physical properties of the elastic body, it is preferable to add (B3) in an amount not exceeding 10% by weight. When (B3) is more than 10% by weight, the crosslink density is increased, the function as an elastic body is reduced, and the stress whitening property tends to be reduced.

Further, (B2) and (B3) are not always required depending on the amount and use of the graft-linking agent.

The total amount of (B1) to (B3) is 100
0.1 to 5 parts by weight of the graft crosslinking agent is used per part by weight.

As the graft-crossing agent in the polymer (B) of the present invention, the same graft-crossing agent as in the polymer (A) can be used, and based on 100 parts by weight of the total amount of (B1) to (B3). 0.1 to 5 parts by weight is used. The amount of the grafting agent is important and the polymers (B) and (A)
(D), at least 0.1 for grafting with (C)
It is necessary to be parts by weight, and if it exceeds 5 parts by weight, the physical properties of the elastic body tend to deteriorate.

TMPM is 10% in the polymer (B).
Although the weather resistance is sufficiently improved in the range of not more than part by weight, it is not always necessary in the polymer (B) if the content of TMPM in the multilayer structure polymer of the present invention is sufficient to impart weather resistance. . Further, the amount is preferably 0.01 to 5 parts by weight in order to have less influence on the multilayer structure polymer and obtain more sufficient weather resistance.

The content of the polymer (B) in the entire multilayer polymer of the present invention is from 10 to 50 parts by weight, preferably higher than the content of the innermost polymer (A). It is preferable for extracting the function and improving the impact strength.

Further, the outermost layer polymer (C) in the present invention
Is an alkyl methacrylate (C1) having 51 to 100% by weight of an alkyl group having 1 to 4 carbon atoms, 0 to 49% by weight
The monomer (C2) having a copolymerizable double bond can be used in this range depending on the desired physical properties.

As the alkyl methacrylate (C1) in the present invention, those similar to (A1) can be mentioned, but methyl methacrylate is preferred from the viewpoint of transparency.

As the monomer (C2) in the present invention, those similar to (A2) can be mentioned. In order to improve the appearance and the like, (C2) is preferably the alkyl acrylate used for the polymers (A) and (B), and most preferably butyl acrylate.

The total amount of (C1) and (C2) is 100
0.01 to 10 parts by weight of TMPM is used per part by weight.

In the present invention, TMPM means 2,2,6,6-tetramethylpiperidyl (meth) acrylate or 1,2,2, (meth) acrylate having the structure shown below.
2,6,6-pentamethylpiperidyl. The TMP
M has a (meth) acryl group in the molecule, and is characterized by having excellent copolymerizability with an acrylic monomer.

[0035]

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The polymer (C) is the outermost layer which greatly affects the weather resistance of the multilayer polymer of the present invention, and the polymer (C) contains at least TMPM of less than 0.01 part by weight. Sufficient light stability and weather resistance cannot be exhibited. Also,
When TMPM is used in an amount of more than 10 parts by weight, it tends to affect physical properties such as transparency of the multilayer polymer of the present invention. The amount is preferably 0.01 to 10 parts by weight, more preferably 0.03 to 3 parts by weight, in order to obtain a more sufficient weather resistance with less influence on the multilayer structure polymer of the present invention.

Further, since the polymer (C) affects the moldability and mechanical properties of the multilayer polymer of the present invention, the glass transition temperature is preferably at least 50 ° C.
Therefore, the monomers (C1) and (C2) have a glass transition temperature of 5
Careful selection is made so that the temperature is 0 ° C. or higher, and the composition ratio is determined.

The glass transition temperature (Tg) of the present invention can be calculated from the value of Tg described in, for example, the Polymer Handbook.
ox Equation 1 / Tg = a1 / Tg1 + a2 / Tg2.

The content of the polymer (C) in the entire multilayer structure polymer of the present invention is 30 to 80 parts by weight, preferably 40 to 60 parts by weight.

The intermediate layer polymer (D) of the present invention comprises a polymer (B) in the basic structural unit consisting of the innermost layer polymer (A), the second layer polymer (B), and the outermost layer polymer (C). ) And the polymer (C) have at least one layer. In order to improve the stress whitening property and transparency of the multilayer polymer, two or more layers may be used.

The intermediate layer polymer (D) of the present invention comprises 10 to 90
% By weight of an alkyl acrylate having an alkyl group having 1 to 8 carbon atoms (D1), 10 to 90% by weight of an alkyl acrylate having 1 to 4 carbon atoms
Alkyl methacrylate having an alkyl group (D
2) 0 to 20% by weight of a monomer having a copolymerizable double bond (D3), 0 to 10% by weight of a polyfunctional monomer (D
4) can be used in this range according to desired physical properties.

The polymer (D) is obtained by mixing the polymers (B) and (C)
It is necessary to set the amount of the acrylate (D1) within a range such that the amount of the acrylate (D1) monotonously decreases from the polymer (B) toward the polymer (C). There is. In this sense, the acrylate (D1) in the present invention includes the same acrylates as (A1) and (B1), and butyl acrylate is particularly preferable.

Examples of the methacrylate (D2) in the present invention include the same methacrylates as (A1) and (C1), and particularly preferred is methyl methacrylate.

The monomers (D3) and (D4) are the same as the monomers (B2) and (B3) of the polymer (B) for the same reason as (D1) and (D2). It is preferable to use one.

The total amount of (D1) to (D4) is 100
0.1 to 5 parts by weight of the graft crosslinking agent is used per part by weight.

The amount of the graft-linking agent is important and is at least 0.1 to graft the polymers (D) and (C).
One part by weight is required, and if it exceeds 5 parts by weight, physical properties such as stress whitening tend to deteriorate.

TMPM is 10% in the polymer (D).
Although the weather resistance is sufficiently improved in the range of not more than part by weight, it is not always necessary in the polymer (D) if the content of TMPM in the multilayer structure polymer of the present invention is sufficient to impart weather resistance. . Further, the amount is preferably 0.01 to 5 parts by weight in order to have less influence on the multilayer structure polymer and obtain more sufficient weather resistance.

The content of the polymer (D) in the multilayer polymer of the present invention is preferably in the range of 5 to 35 parts by weight, and if it is less than 5 parts by weight, it loses its function as an intermediate layer and exceeds 35 parts by weight. And the balance as a whole polymer is lost.

The multi-layered polymer of the present invention comprises each of the above (A),
Although it is composed of the polymer layers (B), (C) and (D), the gel content is at least 50% by weight or more, preferably 60 to obtain excellent stress whitening property.
More than% by weight is required. The gel content in this case means that a 1% by weight acetone solution of the multilayer structure polymer is prepared, left overnight at 25 ° C., refluxed for 4 hours, and then centrifuged.
It refers to the weight percentage of insoluble matter after centrifugation at 000 rpm for 60 minutes. From the viewpoint of moldability, the smaller the gel content, the better, and it is more preferable that the gel content does not exceed about 80% by weight.

Further, TMPM is contained in an amount of 0.01 to 5% by weight, preferably 0.1% by weight, based on the whole of the multilayer structure polymer of the present invention.
２2% by weight must be copolymerized. 0.0
If it is less than 1% by weight, there is no effect of improving light resistance.
If it exceeds 5% by weight, the weather resistance does not change and is uneconomical, and adverse effects on physical properties are also considered.

Various additives may be added to the multi-layered polymer of the present invention depending on its use. In particular, it is preferable to include an ultraviolet absorber since the weather resistance is further improved. . This is because the reactive light stabilizer and the ultraviolet absorber, which are the features of the present invention, have a synergistic effect to further improve the weather resistance. Any known ultraviolet absorber may be used, and examples thereof include benzotriazole-based, triazine-based, and benzophenone-based ultraviolet absorbers. Among them, a molecular weight of 4 such as Tinuvin 234 (manufactured by Ciba-Geigy), Adekastab LA-31 (manufactured by Asahi Denka Kogyo), etc.
A benzotriazole-based ultraviolet absorber having a molecular weight of 400 or more, and a triazine-based ultraviolet absorber having a molecular weight of 400 or more, such as Tinuvin 1577 (manufactured by Ciba Geigy), are preferred because they cause less bleed-out during molding. Further, it is particularly preferable to copolymerize a reactive ultraviolet absorber such as RUVA-93 (manufactured by Otsuka Chemical Co., Ltd.), since there is no bleed-out during molding. Further, the content of the ultraviolet absorber is 0.1 parts by weight or more can obtain a sufficient effect, it is preferable to use 10 parts by weight or less that does not affect the physical properties of the multilayer structure polymer,
A content of 0.5 to 3 parts by weight that balances physical properties and weather resistance is more preferable.

The multi-layered polymer of the present invention may be produced by any known polymerization method in the order of the polymers (A), (B), (D) and (C). As an effective production method, each of the polymers is (A), (B),
In order to form a multilayer structure from the inside in the order of (D) and (C), it is advantageous to use a multi-stage polymerization, preferably a multi-stage seed emulsion polymerization method. The particle size of the final polymer at this time is not particularly limited, but is preferably about 500 to 3000 because a structure having a good balance between stress whitening property and mechanical properties can be obtained.

When the thickness of the acrylic resin film in the present invention is more than 300 μm, the rigidity increases and it is not preferable as a protective film. Therefore, the thickness of the acrylic resin film needs to be 300 μm or less.
The method for producing the acrylic resin film is not particularly limited, and known methods such as a melt extrusion method such as a T-die method and an inflation method, a solution casting method, and a calender method can be used. The T-die method is most advantageous in that the adjustment is easy.

The acrylic resin film of the present invention is used for PVC (PVC window frames, PVC wallpaper, other PVC interior and exterior building materials), PC (PC corrugated sheet, PC flat plate), and others (high-brightness reflective material, Lighting / insulation materials, solar cells, laminate A
BS molded product).

[0055]

The present invention will be described in detail with reference to the following examples.

The abbreviations used in the examples are as follows.

Methyl methacrylate MMA butyl acrylate BA 1,3-butylene glycol dimethacrylate BD allyl methacrylate AMA cumene hydroperoxide CHP formaldehyde sodium sulfoxylate SFS Also, the Tg of the outermost layer polymer used in the examples can be found, for example, in a polymer handbook. From the described value of Tg, Fox
1 / Tg = a1 / Tg1 + a2 / Tg2.

Further, the gel content, total light transmittance, tensile strength and elongation, stress whitening property and weather resistance in the examples were determined by the following methods.

Gel content: A 1% by weight acetone solution of the multi-layered polymer was prepared, left standing at 25 ° C. for 24 hours, refluxed for 4 hours, and centrifuged at 14000 rpm for 60 minutes in a centrifuge. Measure insolubles.

Total light transmittance: 50 μm film was AST
Reflection and transmittance meter HR-1 based on MD1003-61
It was measured by Model 00 (manufactured by Murakami Color Research Laboratory).

Roll dirt: In order to observe bleed-out during molding, dirt on a cooling roll during film formation was visually evaluated.

・: No stain is generated on the roll for 1 minute or more.

×: The roll is stained in less than one minute.

Tensile strength and elongation: A film having a thickness of 50 μm was used to prepare a measurement sample having a width of 1.5 cm and a measurement length of 5 cm, and the measurement was carried out using STOROGRAPH-T (manufactured by Toyo Seiki Co., Ltd.).

Weather resistance: A 50 μm film having a thickness of 3
Approximately 6cm laminated on a mm polycarbonate plate
A 4.5 cm sample plate was placed in room temperature ion-exchanged water for 24 hours.
After the sample was immersed for a period of time and dried sufficiently, an eye super UV tester (manufactured by Dainippon Plastics Co., Ltd.)
The color difference (ΔE) after the treatment for 0 hour was measured.

Stress whitening: 180 μm of 50 μm film
The state at the time of bending was visually observed.

・: Almost no whitening.

×: Whitening occurs.

Example 1 A polymerization vessel equipped with a condenser was charged with 250 parts by weight of ion-exchanged water, 2 parts by weight of an ester soda salt of sulfosuccinic acid, and 0.05 part by weight of SFS, and stirred under a nitrogen atmosphere. 1.6 parts by weight, BA 8 parts by weight, BD 0.4 parts by weight, AMA 0.1 parts by weight, ADK STAB LA-82 (manufactured by Asahi Denka Kogyo KK, 1,2,2, methacrylic acid) 6,6-pentamethylpiperidyl) and 0.04 part by weight of CHP were charged. After the temperature was raised to 70 ° C., the reaction was continued for 60 minutes to complete the polymerization of the innermost layer polymer (A).

Subsequently, 1.5 parts by weight of MMA and 2 parts by weight of BA
2.5 parts by weight, 1 part by weight of BD, 0.25 parts by weight of AMA, 0.1 parts by weight of ADK STAB LA-82, and C
0.02 parts by weight of HP was added for 60 minutes and polymerized to complete the polymerization of the second layer polymer (B).

Subsequently, 5 parts by weight of MMA, 5 parts by weight of BA, 0.1 parts by weight of AMA, 0.04 parts by weight of Adekastab LA-82 and 0.04 parts by weight of CHP were used as the intermediate layer polymer (D).
Was reacted with 49.5 parts by weight of MMA, 5.5 parts by weight of BA, and 0.24 parts by weight of ADK STAB LA-82. C) was completed to obtain a multilayer polymer having a final particle size of 1200 μm.

This was salted out using 5 parts by weight of calcium chloride with respect to 100 parts by weight of the multilayer structure polymer, washed and dried, and an ultraviolet absorber LA-31 (manufactured by Asahi Denka Kogyo KK) 2
A 50 μm film was formed by adding parts by weight and shaping.

The gel content of the obtained multilayer structure polymer, the Tg of the outermost layer polymer, the particle diameter, the roll contamination during shaping, the total light transmittance of the film obtained by shaping, and the tensile strength and elongation Table 1 shows the results of the evaluation of the whitening, stress whitening, and weather resistance.

Example 2 Adekastab LA-87 instead of Adekastab LA-82 of the first layer polymer (A)
(Asahi Denka Kogyo KK, 2,2,6,6-methacrylic acid
0.05 parts by weight of tetramethylpiperidyl) and 0.25 parts by weight of ADK STAB LA-87 instead of ADK STAB LA-82 of the second layer polymer (B), and ADK STAB LA- of the intermediate layer polymer (D) 0.1 part by weight of ADK STAB LA-87 instead of 82, and the outermost layer polymer (C)
Adekastab LA instead of Adekastab LA-82
Using 0.6 parts by weight of -87 and Tinuvin 234 (manufactured by Nippon Ciba Geigy Co., Ltd.) in place of the UV absorber LA-31
Was used in the same manner as in Example 1 except for using 5 parts by weight of a polymer having a multilayer structure and a film of 50 μm.

The gel content of the obtained multilayer structure polymer, the Tg of the outermost layer polymer, the particle size, the roll contamination during shaping, the total light transmittance and the tensile elongation of the film obtained by shaping Table 1 shows the results of the evaluation of the whitening, stress whitening, and weather resistance.

(Example 3) CG28-906 (manufactured by Nippon Ciba Geigy Co., Ltd., acrylic acid 1,2,2,6,6-) instead of Adekastab LA-82 of the first layer polymer (A)
Pentamethylpiperidyl) and 0.05 parts by weight of ADK STAB CG28-906 instead of ADK STAB LA-82 of the second layer polymer (B), and ADK STAB LA- of the interlayer polymer (D). 0.02 parts by weight of Adekastab CG28-906 in place of 82, 0.12 parts by weight of Adekastab CG28-906 in place of Adekastab LA-82 of the outermost layer polymer (C), and ultraviolet absorber LA-31 Instead of using 1 part by weight of Tinuvin 1577 (manufactured by Ciba Geigy K.K.), a multilayer structure polymer and a 50 μm film were obtained in the same manner as in Example 1.

The gel content of the obtained multilayer structure polymer, the Tg of the outermost layer polymer, the particle diameter, the roll contamination during shaping, and the total light transmittance and tensile elongation of the film obtained by shaping. Table 1 shows the results of the evaluation of the whitening, stress whitening, and weather resistance.

Example 4 250 parts by weight of ion-exchanged water, 2 parts by weight of ester soda salt of sulfosuccinic acid and 0.05 part by weight of SFS were charged into a polymerization vessel equipped with a condenser, and stirred under a nitrogen atmosphere. 1.6 parts by weight, BA 8 parts by weight, BD 0.4 parts by weight, AMA 0.1 parts by weight, and CHP 0.04 parts by weight. After the temperature was raised to 70 ° C., the reaction was continued for 60 minutes to complete the polymerization of the innermost layer polymer (A).

Subsequently, 1.5 parts by weight of MMA and 2 parts by weight of BA
2.5 parts by weight, 1 part by weight of BD, 0.25 parts by weight of AMA, and 0.02 parts by weight of CHP were added in 60 minutes,
The polymerization was completed to complete the polymerization of the second layer polymer (B).

Subsequently, a mixture of 5 parts by weight of MMA, 5 parts by weight of BA, 0.1 parts by weight of AMA, and 0.01 parts by weight of CHP was reacted as the intermediate layer polymer (D). , 49.5 parts by weight of BA, 5.5 parts by weight of BA, 0.4 parts by weight of Adekastab LA-82, and 2 parts by weight of a reactive ultraviolet absorber RUVA-93 (manufactured by Otsuka Chemical Co., Ltd.). The outermost layer polymer (C) was completed to obtain a multilayer polymer having a final particle diameter of 1200.

This was salted out using 5 parts by weight of calcium chloride with respect to 100 parts by weight of the multilayer structure polymer, washed, dried, and shaped to form a 125 μm film.

The gel content of the obtained multilayer structure polymer, the Tg of the outermost layer polymer, the particle size, the roll contamination during shaping, the total light transmittance of the film obtained by shaping, and the tensile strength and elongation Table 1 shows the results of the evaluation of the whitening, stress whitening, and weather resistance.

(Comparative Example 1) A multi-layered polymer having a thickness of 50 μm was obtained in the same manner as in Example 1 except that LA-82 was not used.
Was obtained.

The gel content of the obtained multilayer structure polymer, the Tg of the outermost layer polymer, the particle size, the roll contamination during shaping, the total light transmittance and the tensile elongation of the film obtained by shaping. Table 1 shows the results of the evaluation of the whitening, stress whitening, and weather resistance.

(Comparative Example 2) Adekastab LA-57 (manufactured by Asahi Denka Co., Ltd.) as a light stabilizer without using LA-82.
A multilayer structure polymer and a 50 μm film were obtained in the same manner as in Example 1 except that 0.4 part by weight was used during kneading.

The gel content of the obtained multilayer structure polymer, the Tg of the outermost layer polymer, the particle size, the roll contamination during shaping, the total light transmittance and the tensile elongation of the film obtained by shaping. Table 1 shows the results of the evaluation of the whitening, stress whitening, and weather resistance.

[0087]

[Table 1]

[0088]

The multilayer structure polymer of the present invention is characterized in that the light stabilizer does not bleed out or volatilize during molding and kneading, and the acrylic resin film composed of the multilayer structure polymer has excellent transparency and stress whitening properties, and is resistant to weathering. It has improved properties and is suitable for use in protective films and sheets.

Claims (3)

[Claims] 1. An innermost layer polymer (A) of 5 to 35 parts by weight, a second layer polymer (B) of 10 to 50 parts by weight,
0 to 80 parts by weight of the outermost layer polymer (C), and at least one intermediate layer of 5 to 35 parts by weight such that the amount of alkyl acrylate monotonically decreases from the polymer (B) toward the polymer (C). A weather resistance comprising a layer polymer (D), each of which is polymerized in the order of (A), (B), (D) and (C), and having a gel content of at least 50% by weight or more. Multilayer polymer with improved properties. (A) 80 to 100% by weight of an alkyl acrylate having an alkyl group having 1 to 8 carbon atoms or an alkyl methacrylate having an alkyl group having 1 to 4 carbon atoms (A1);
-20% by weight of a monomer having a copolymerizable double bond (A2), 0-10% by weight of a polyfunctional monomer (A3),
And an innermost layer polymer (A) having a composition of 0.1 to 5 parts by weight with respect to 100 parts by weight of the total amount of (A1) to (A3). (B) 80 to 100% by weight of an alkyl acrylate having an alkyl group having 1 to 8 carbon atoms (B1); 0 to 20% by weight of a monomer having a copolymerizable double bond (B2);
-10% by weight of a polyfunctional monomer (B3), and (B
0.1 to 100 parts by weight of the total amount of 1) to (B3)
A second layer polymer (B) having a composition of 5 parts by weight of a graft crosslinking agent. (C) 51 to 100% by weight of an alkyl methacrylate having an alkyl group having 1 to 4 carbon atoms (C1), 0 to 49% by weight of a monomer having a copolymerizable double bond (C2),
And 0.01 to 10 parts by weight based on 100 parts by weight of the total amount of (C1) and (C2),
An outermost polymer (C) comprising a 2,6,6-tetramethylpiperidine monomer and having a glass transition temperature of at least 50 ° C. Embedded image (D) 10 to 90% by weight of an alkyl acrylate having an alkyl group having 1 to 8 carbon atoms (D1), 10 to 90% by weight of an alkyl methacrylate having an alkyl group having 1 to 4 carbon atoms (D2), 0 to 20% % By weight of a monomer having a copolymerizable double bond (D3), 0 to 10% by weight of a polyfunctional monomer (D4), and (D1) to (D4) in 100 parts by weight. On the other hand, an intermediate layer polymer (D) comprising a composition of 0.1 to 5 parts by weight of a graft crossing agent and comprising at least one layer between the second layer polymer (B) and the outermost layer polymer (C). 2. 0.1 parts by weight based on 100 parts by weight of the multilayer structure polymer.
2. The multilayer structure polymer according to claim 1, comprising from 10 to 10 parts by weight of an ultraviolet absorber. 3. An acrylic resin film comprising the polymer having a multilayer structure according to claim 1 and having a thickness of 300 μm or less.