JPS627756A - Impact-resistant methacryl resin composition - Google Patents

Abstract

PURPOSE:To provide the titled composition having excellent weather-resistance and low-temperature impact resistance and composed of a methacrylate resin and a copolymer produced by enclosing a specific thickened rubbery copolymer with a crosslinked acrylate copolymer and grafting methyl methacrylate, etc., thereto. CONSTITUTION:(A) A rubbery polymer latex composed of an alkyl acrylate and 1,3-butadiene is thickened with (B) (i) an acid group-containing copolymer in a polymer latex obtained by the emulsion polymerization of an unsaturated acid and an alkyl acrylate and (ii) a specific oxyacid salt, and the thickened rubber is added with (C) an alkyl acrylate, a styrene compound and a copolymerizable polyfunctional monomer. The mixture is polymerized to obtain an elastomer having double structure. The elastomer is mixed with (D) a graft- copolymer having a multi-layer structure and obtained by the polymerization of a monomer (mixture) composed mainly of methyl methacrylate and (E) a methacrylate resin composed mainly of methyl methacrylate.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an impact-resistant methacrylic resin composition, and more particularly to a methacrylic resin composition that has excellent weather resistance and impact resistance at low temperatures.

[Conventional technology]

Methacrylic resin has excellent transparency and optical properties among plastic materials, and is also extremely superior in surface gloss, weather resistance, colorability with dyes and pigments, and moldability. It can be used in many fields such as lighting, signboards, window materials, optical lenses, tail lenses, meter covers, dust covers, displays, tableware, optical applications, building materials, electrical equipment parts, vehicle parts, decoration fields, and miscellaneous goods. It is used.

However, methacrylic resins have a problem in that they lack impact resistance, and there is a strong demand for improvement in each application field.

Various proposals have been made for a long time as methods for improving the impact resistance of methacrylic resins.

The most common and effective method is to add an elastomer that is rubbery at room temperature, such as an unsaturated rubbery polymer mainly composed of butadiene, or acrylic acid, to a continuous resin phase mainly composed of methyl methacrylate. A method of discontinuously dispersing acrylic acid ester polymers mainly composed of butyl, 2-ethylhexyl acrylate, etc., or saturated rubber-like elastic materials such as ethylene/vinyl acetate copolymers in the form of particles has been adopted. There is.

Although the introduction of an unsaturated rubber-like elastic material is excellent in terms of impact resistance, there is a problem of poor weather resistance due to the unsaturated bonds in the polymer main chain. Although □ is superior in terms of weather resistance, its glass transition point is higher than that of diene-based rubber-like elastic bodies.

Furthermore, the elastic modulus and elastic recovery of the rubber component itself are low, and the graft polymerizability with the hard resin component is poor, resulting in poor impact resistance, transparency, surface gloss, etc. especially in low-temperature regions, and fluid patterns. There are also problems with the surface appearance, such as the appearance of

In general, these rubber-like elastic bodies are discontinuous particles □ Continuous phase of hard resin such as methacrylic resin 1
When synthesizing an impact-resistant resin composition consisting of a two-component system uniformly dispersed in a phase, important factors include the composition of the rubbery elastomer, particle size, degree of crosslinking, and graft polymerization of the hard resin phase to the rubber phase. In fact, the quality and balance of the resin properties of the final resin composition are greatly influenced by these factors.

That is, the lower the glass transition point of the rubber-like elastic body, the better the effect of developing impact resistance, and the smaller the particle diameter, the better the transparency, but the lower the effect of developing impact resistance.

Regarding the degree of crosslinking, the higher the crosslinking density, the better the surface appearance such as surface gloss and flow pattern, but the disadvantage is that the impact resistance is poor.

In addition, the degree of graft polymerization of the hard resin phase to the rubber-like elastic body greatly controls the compatibility and dispersibility of the rubber-like elastic body in the continuous resin phase, and influences the impact resistance, transparency, and It affects many properties such as stress whitening properties, surface gloss, and flow processability, and when using saturated rubber-like elastomers, graft polymerizability is generally low and special consideration must be taken. However, since the degree of grafting has a great effect on the final physical properties of the resin, particularly transparency, surface gloss, and flow processability, it is necessary to control the graft polymerization reaction. Furthermore, the larger the molecular weight of the hard resin phase to be grafted, the more effective it is in terms of impact resistance, but it is conversely inferior in terms of surface appearance and moldability.

As mentioned above, the behavior of each factor is individual and has advantages and disadvantages, and it is extremely difficult to efficiently design the balance of the overall resin properties of impact-resistant methacrylic resin. The reality is that a methacrylic resin molding material that has transparency, surface gloss, and moldability comparable to that of methacrylic resins, and particularly has excellent impact resistance in the low-temperature range, has not yet appeared.

In recent years, in impact-resistant resin compositions or impact-resistant methacrylic resin compositions in which the rubber phase is an acrylic ester-based elastomer with excellent weather resistance, the effect of developing impact resistance in the rubber phase,
In order to improve the transparency and stress whitening resistance of molded products, pearl-like luster caused by deformation of rubber particles during the molding process, and weather resistance, methods have been proposed in which hard resins are contained inside rubber particles. Although these methods are certainly effective, when viewed as a methacrylic resin material, it is still quite inferior in terms of transparency and surface gloss, and Furthermore, impact resistance at low temperatures is low.

As a composition having excellent weather resistance and low-temperature impact resistance or a method for producing the same, a polyvalent allyl compound and a carbon number of 1 to 1 are used.
Using a monomer mixture of a specific amount of an acrylic acid ester having three alkyl groups and another copolymerizable vinyl compound, graft polymerization is performed in the presence of a diene polymer to further obtain an aromatic vinyl compound, A method for producing impact-resistant thermoplastic resins by emulsion polymerization of specific amounts of methacrylic acid esters and vinyl cyanide compounds (Japanese Unexamined Patent Publication No. 57-1
67308) and diene polymers with 2 to 12 carbon atoms.
A mixture of a specific amount of an acrylic acid alkyl ester having an alkyl group and a polyfunctional vinyl monomer is graft-polymerized, and a specific amount of acrylonitrile or methacrylonitrile and a carbon number of 1 to 4 are added to the resulting graft polymer. a specific amount of methacrylic acid alkyl ester having an alkyl group of
and a method for producing impact-resistant graft polymers (Japanese Patent Publication No. 47-47
No. 863, JP-A-56-86918), etc. are known.

However, by any of these methods, it is difficult to obtain a methacrylic resin composition with excellent weather resistance and low-temperature impact resistance.

The reason for this is that with any of the above methods, the product obtained is a powder-like polymer, which is difficult to mold, and may cause discoloration or deterioration due to heat during molding, resulting in poor productivity. The polymer obtained from the monomers etc. that make up all of these methods cannot be called a methacrylic resin in terms of transparency, coloring due to heat, weather resistance, water resistance, etc.

For example, Japanese Patent Publication No. 47-47863 discloses that a diene polymer is polymerized with a monomer mainly consisting of an acrylic acid alkyl ester having an alkyl group having 2 to 12 carbon atoms, or a mixture thereof, and an acrylonitrile monomer is further added to the diene polymer. A technique has been disclosed in which specific amounts of a methacrylic acid alkyl ester monomer, and a styrene monomer are graft-polymerized.
With this technique, it is virtually difficult to obtain a composition that has excellent transparency, appearance, and weather resistance comparable to methacrylic resins.

[Problem that the invention seeks to solve]

Under the current situation as described above, the purpose of the present invention is to provide a methacrylic resin composition that has excellent impact resistance, especially impact resistance in a low temperature range, has little thermal coloring property, and has good weather resistance.
As a result of intensive studies, we found that a rubber-like copolymer latex whose main constituent units are a specific amount of acrylic acid alkyl ester units with a specific structure and a specific amount of butadiene units, and a specific amount of specific polymerizable unsaturated acid units. An acid group-containing copolymer latex whose main constituent units are a specific amount of a specific acrylic acid alkyl ester unit and an oxyacid salt having a specific structure are added and enlarged, and then a specific composition is obtained. By combining a special formulation of polymerizing a monomer mixture containing a double-layer structure to form a double-structure elastic body, and grafting a monomer mainly composed of methyl methacrylate to this, the resulting multi-layer structure graft copolymer The present invention has been accomplished by discovering that the objects of the present invention can be achieved by mixing a methacrylic resin containing methyl methacrylate as a main component in a specific range.

[Means for solving problems]

The impact-resistant methacrylic resin composition of the present invention comprises (a) 20 to 70% by weight of acrylic acid alkyl ester units whose alkyl group has 1 to 8 carbon atoms, and 30% by weight of 1°3-butadiene units.
~80% by weight, and 0 to 10% by weight of other monofunctional or polyfunctional vinyl monomer units copolymerizable with these [II] latex polymer (b) At least one member selected from the group consisting of acrylic acid, methacrylic acid, itaconic acid, crotonaceous acid, maleic acid, fumaric acid, cinnamic acid, sorbic acid, and p-styrenesulfonic acid, per 100 parts by weight. 3 to 40% by weight of unsaturated acid units of Acid group-containing copolymers (Al, and copolymers containing Al and 2nd and Third
At least one type of oxyacid selected from alkali metal salts or alkaline earth metal salts of oxyacids, salts of zinc, nickel, and aluminum, mainly consisting of elements selected from the group of elements belonging to the periodic group ( The rubbery copolymer [II] latex is enlarged by adding 0.1 to 5 parts by weight of Bl, and the average particle diameter is adjusted to 0.12 to 0.4.
μm range, and furthermore, this enlarged rubbery copolymer [I
]' 5 to 75 parts by weight of latex, 69.9 to 89.9 weight % of at least one acrylic acid alkyl ester whose alkyl group has 1 to 8 carbon atoms, and styrene alone or a mixture of styrene and its derivatives. Monomer mixture (C) consisting of 10 to 30% by weight and 0.1 to 10% by weight of a polyfunctional monomer copolymerizable with this and having two or more carbon-carbon bonds in one molecule (C) 25- In the presence of 100 parts by weight of the resulting double structure elastic body [■], 95 parts by weight of methyl methacrylate, 80 to 100% by weight of methyl methacrylate, and an alkyl group having 1 to 8 carbon atoms were added. Polymerization of 5 to 1000 parts by weight of a monomer or a mixture thereof (D) consisting of 0 to 20% by weight of at least one kind of acrylic acid alkyl ester and 0 to 10% by weight of another vinyl monomer copolymerizable with this. and a methacrylic resin [IV] consisting of 80 to 100% by weight of methyl methacrylate units and 0 to 20% by weight of other copolymerizable monomer units.
The present invention is characterized in that the content of the double structure elastic body [■] in the mixture is 1 to 50% by weight. A rubber-like copolymer with a controlled refractive index that has excellent weather resistance is enlarged with a base fertilizer and a special compound indicated by (Bl) to have a particle size within a specific range. wrapped in a controlled cross-linked acrylic ester copolymer,
A monomer containing methyl methacrylate as the main component or a mixture thereof is graft-polymerized to the obtained double structure elastic body [■], and a specific amount of the graft copolymer [I] and methyl methacrylate as the main component are graft-polymerized. A particularly important point is that the rubber-like copolymer is enlarged with the compound represented by the above-mentioned polymer and (Bl), and that this enlargement When obtaining a double structure elastic body [111] using a rubber-like copolymer,
A specific amount of an acrylic acid alkyl ester and a styrene monomer having an alkyl group having 1 to 8 carbon atoms, and a polyfunctional monomer having two or more specific carbon-carbon double bonds in one molecule. It's about using it.

The rubbery copolymer [I] latex of the present invention comprises 20 acrylic acid alkyl esters in which the alkyl group has 1 to 8 carbon atoms.
~70% by weight and 30-80% by weight of 1,3-butadiene
It is a copolymer of a monomer mixture consisting of these and 0 to 10% by weight of vinyl monomers of other copolymerizable monofunctional or polyfunctional monomers, and after enlargement, It is necessary to contain 5 to 75 parts by weight, more preferably 10 to 60 parts by weight, inside the double structure elastic body [11].

If the amount is less than 5 parts by weight, the effect of improving the impact resistance in the low temperature range will be small and the transparency will also decrease.

On the other hand, if it exceeds 75 parts by weight, the surface gloss tends to decrease and the weather resistance also tends to decrease.

The acrylic acid alkyl ester having an alkyl group having 1 to 8 carbon atoms used in the polymerization of the rubbery copolymer [1) is not particularly limited, but particularly preferably butyl acrylate, 2-ethylhexyl acrylate, and the like.

If the content of the acrylic ester in the rubbery copolymer (I) is less than 20% by weight, weather resistance and heat resistance stability will decrease, and if it exceeds 70% by weight, impact resistance at low temperatures will decrease. decreases.

In addition, other copolymerizable monomers used in the polymerization of rubbery copolymer [13] include monofunctional monomers typified by styrene, acrylonitrile, methacrylic acid alkyl esters such as methyl methacrylate, and divinyl These are polyfunctional monomers such as benzene, ethylene glycol dimethacrylate, butylene glycol diacrylate, trimethylolpropane triacrylate, and pentaerythritol tetraacrylate.

The polymerization itself can be carried out according to known emulsion polymerization techniques. Incidentally, when obtaining the rubbery copolymer [I], it is also possible to add a chain transfer agent such as mercaptan.

The particle size of the rubbery copolymer [I] obtained by polymerization is preferably in the range of 0.03 to 0620 μm, and 0.05 μm.
The range of 0.15 μm is more preferable.

Outside this range, it will be difficult to control the polymerization rate and polymerization temperature, the desired particle size will not be achieved during the subsequent enlargement process, the polymerization system will become unstable, and the impact resistance of the final composition will deteriorate. Problems such as deterioration of appearance may occur.

Next, a copolymer containing at least one unsaturated acid monomer selected from acrylic acid, methacrylic acid, itaconic acid, crotonic acid, fumaric acid, cinnamic acid, rubic acid, and p-styrenesulfonic acid. (A) is used in combination with a salt of an oxyacid (Bl, described below) to thicken the rubbery copolymer [1''l latex.

It is essential that this copolymer contains an unsaturated acid monomer and an acrylic acid alkyl ester. At least one type is selected.

However, by adding an acrylic acid alkyl ester,
It is possible to use 0 to 40% by weight of other copolymerizable monomers. Examples of such copolymerizable monomers include monomers such as methyl methacrylate and other methacrylic esters, styrene and α-methylstyrene and other styrene derivatives, and acrylonitrile.

The amount of the unsaturated acid monomer used is 3 to 40% by weight. 3
If it is less than i% by weight, the enlarging ability is small, and if it exceeds 40 wt%, the enlarging ability is too strong, which is not preferable because it produces particles larger than 1 μm.

In addition, the optimal content of unsaturated acid monomers varies depending on the degree of hydrophilicity of the alkyl acrylate ester used; However, if the amount of unsaturated acid monomer increases, the latex will be destroyed, which is not preferable.

Conversely, when the hydrophilicity of the alkyl acrylate ester is low, the enlargement effect is small in the region where the amount of unsaturated acid monomer is low, and it is not effective until the amount of unsaturated acid monomer increases beyond a certain level. doesn't appear. For example, in the case of highly hydrophilic methyl acrylate and ethyl acrylate, it is optimal when the amount of unsaturated acid monomer is 5 to 10% by weight.
In the case of butyl acrylate and 2-ethylhexyl acrylate, which are hydrophobic acrylic esters in which the alkyl group has 4 or more carbon atoms, the amount of unsaturated acid monomer is 13 to 20% by weight.
It is optimal in the case of In addition, when a highly hydrophilic acrylic acid alkyl ester is used, the amount of unsaturated acid monomer is 5 to 5.
Even at 10% by weight, the system tends to become unstable,
Therefore, there is a problem that currents (coarse particles) are likely to be generated, but if a hydrophobic acrylic acid alkyl ester as described above is used, the system will not become unstable.
Uniform enlarged particles are often obtained.

The acid group-containing copolymer latex used in the present invention contains 3 to 40% by weight of at least one unsaturated acid selected from the above-mentioned unsaturated acids, and an alkyl group having 1 to 40 carbon atoms.
12 at least one acrylic acid alkyl ester 3
5-97% by weight and 0-97% of other copolymerizable monomers
Although it is possible to polymerize a monomer mixture consisting of 40% by weight at once, it is possible to polymerize a portion of the monomer mixture that is 5 to 90% by weight and does not contain the above unsaturated acid. After that, the remainder 95 of the monomer containing the unsaturated acid is
It is also possible to obtain a latex having a multilayer structure of two or more layers by successively polymerizing ~10% by weight without forming new particles, that is, by polymerizing in two or more stages.

Alkali metal salts or alkaline earth metal salts of oxyacids, zinc, nickel, mainly containing elements selected from the group of elements belonging to the second and third periods of groups 2 to 3 in the periodic table of elements. and at least one oxyacid salt (B) selected from aluminum salts.
, ] Used as a latex thickening agent. Specific examples of such oxygen salts include sulfuric acid, nitric acid, phosphoric acid, potassium, sodium, magnesium, calcium,
Examples include salts with nickel and aluminum. Preferably potassium sulfate, sodium sulfate, magnesium sulfate,
Examples include sodium hydrogen phosphate and magnesium hydrogen phosphate.

The acid group-containing copolymer and oxyacid salt (B
), it is easier to obtain good impact resistance when used in combination (and the final product has excellent transparency and appearance.

Acid group-containing copolymer (Al latex and oxyacid (B)
l is added to the rubbery copolymer [I]. When using these, when the acid group-containing copolymer (A) and the oxyacid salt (Bl) are used together, the total amount of latex added is 100 parts by weight of the solid content of the rubbery copolymer [1,1]. The amount is 0.1 to 5 parts by weight, preferably 0.2 to 4 parts by weight.
Acid group-containing copolymer of Bl (weight ratio to Al is 0.0
The ratio is 1/1 to 10/1, and by adding an appropriate amount, the base rubber can be enlarged more efficiently, and the stability of the obtained large particle diameter rubber latex can also be greatly improved. The particle size of the enlarged rubbery copolymer [II]' is 0.10-0.
50μ, preferably 0.13 to 0.35μ.

When carrying out the enlargement treatment of the present invention using the acid group-containing copolymer (A), it is preferable that the pH of the base rubber (D latex) is 7 or more. Even if a group-containing copolymer latex is added, the enlarging efficiency is low, and it may not be possible to advantageously produce the composition targeted by the present invention.If the pH of this base rubber latex is set to 7 or more, When p is used during the polymerization of this base rubber,
H adjustment may be carried out, or it may be carried out separately before the enlargement treatment.

The rubbery copolymer that was enlarged in this way [:
l] '5 to 75 parts by weight, the alkyl group has 1 to 8 carbon atoms
At least one acrylic acid alkyl ester of 69.
9 to 89.9% by weight and 10 to 30% by weight of styrene alone or a mixture of styrene and its derivatives, and a polyfunctional monomer copolymerizable with this and having two or more carbon-carbon double bonds in one molecule A monomer mixture consisting of 0.1 to 10% by weight of C125 to 95 is added and polymerized, containing the enlarged rubbery copolymer [■]' inside, and crosslinked acrylic acid. Double structure elastic body whose outer layer is composed of ester [
■] is formed.

The acrylic acid alkyl ester having an alkyl group having 1 to 8 carbon atoms in the monomer mixture used to obtain the double structure elastic body Ell) of the present invention may be selected from butyl acrylate, 2-ethylhexyl acrylate, etc. Those selected are preferred, and the acrylic acid alkyl ester and styrene or its derivatives are important for imparting transparency to the resulting composition, and transparency decreases when the composition is outside the above range.

In addition, the addition of a polyfunctional monomer having two or more carbon-carbon double bonds in one molecule is necessary from the viewpoint of impact resistance and surface appearance, and is optimal depending on the type of polyfunctional monomer. Although the amount added varies, it is generally within the above range of 0.1 to 10% by weight.

Examples of such polyfunctional monomers include acrylic acid and α
It is necessary to use an ester of at least one kind selected from , β-substituted acrylic acid and at least one kind of alcohol selected from allyl alcohol, methallyl alcohol, and crotyl alcohol. The intended purpose of the invention is not achieved. Among these, it is particularly preferable to use one selected from allyl acrylate, allyl methacrylate, allyl cinnamate, and allyl sorbate because the impact resistance and appearance of the final composition can be improved.

The above polyfunctional monomers can be used in combination with other polyfunctional monomers.

There is no need to specifically limit other polyfunctional monomers that can be used, but from the perspective of controlling the degree of crosslinking, it is preferable that at least two double bonds have relatively similar reactivity. is ethylene glycol dimethacrylate, ethylene glycol diacrylate, 1
゜Difunctional monomers such as 3-butylene dimethacrylate, tetraethylene glycol diacrylate, and divinylbenzene, or trifunctional monomers such as trimethylolpropane triacrylate, or tetrafunctional monomers such as pentaerythritol tetraacrylate. Each mer can be used alone or in combination.

It is not preferable to use a monomer having a reactive double bond such as triallyl cyanurate alone, and if it is necessary to use this type of monomer,
It is necessary to use it in combination with a crosslinking monomer having two or more double bonds of equal reactivity as described above.

Next, in the presence of the double structure elastic body [■], 80 to 100% by weight of methyl methacrylate and an alkyl group containing 1 carbon atom were added.
At least one type of acrylic acid alkyl ester of ~80
20% by weight of a monomer or a mixture thereof consisting of 0 to 10% by weight of other vinyl monomers copolymerizable therewith) to obtain a multilayered graft copolymer C1).

When the content of methyl methacrylate in the monomer or mixture Q) is 80% by weight, properties such as transparency, heat resistance, and weather resistance are poor, and the acrylic acid copolymerized with it is poor. Examples of acid alkyl esters include methyl acrylate, ethyl acrylate, butyl acrylate, and other vinyl monomers that can be used as copolymerization components include styrene, acrylonitrile, methacrylic acid, Examples include 2-hydroxyethyl methacrylate.

If the amount of acrylic ester exceeds 20% by weight in the monomer or mixture thereof (D+), it is unfavorable in terms of heat resistance and transparency of the final composition, and other copolymerizable vinyl monomers When the weight exceeds 1% by weight, properties such as transparency, weather resistance, and water resistance tend to decrease.

The monomer or mixture thereof) is a double structure elastic body [
1] 5 to 1000 parts by weight, preferably 10 to 500 parts by weight per 100 parts by weight.

If the amount is less than 5 parts by weight, the effect of improving surface gloss and fluidity cannot be obtained, and if it exceeds 1000 parts by weight, the surface gloss and fluidity tend to decrease, resulting in poor productivity, heat coloring, and low temperature. Impact resistance also decreases.

In the method of the invention, monomers or monomer mixtures)
In order to adjust the molecular weight, it is also possible to use a polymerization degree regulator such as mercaptan, if necessary. Examples of the polymerization degree regulator that can be used include alkyl mercaptans, thioglycolic acid and its esters, β-mercaptopropionic acid and its esters, and aromatic layer mercaptans such as thiophenol and thiocresol.

The multilayered graft copolymer obtained by the series of polymerization processes described above can be used with other thermoplastic resins,
Preferably 80-100% by weight of methyl methacrylate and 0
~20% by weight of other vinyl monomers, e.g. from 1 to 4 carbon atoms
The double structure elastic body Cn] is mixed with a methacrylic resin [IV] which is a polymer of an acrylic acid ester having an alkyl group of 1 to 50% by weight.

Since it is particularly preferable to manufacture the multilayered graft copolymer [11] used in the present invention by emulsion polymerization, an example in which emulsion polymerization is used will be described.

After adding deionized water and an emulsifier if necessary to the reaction vessel, the monomer mixture constituting the rubbery copolymer [I] was polymerized, and this was added to the above (Al and H(B)). After enlarging with the compound represented by, a monomer mixture (C1 is added and polymerized, followed by monomer or monomer (2)) to form a double structure elastic body [2] is polymerized.

The polymerization temperature is 30 to 120°C, more preferably 50 to 1
It is 00℃.

The polymerization time varies depending on the type and amount of the polymerization initiator and emulsifier, the polymerization temperature, etc., but is usually 0.5 to 36 hours at each polymerization stage.

The ratio of monomer to water is preferably monomer/water=1/20 to 1/1.

A polymerization initiator and an emulsifier can be added to either or both of the aqueous monomer phases.

Although each monomer can be charged at once or in portions in the polymerization step, a split charging method is more preferable from the viewpoint of heat generation during polymerization.

The emulsifier does not need to be particularly limited as long as it is a commonly used emulsifier (Examples of emulsifiers that can be used include long chain alkyl carboxylates, sulfosuccinic acid alkyl ester salts,
Alkylbenzezosulfonate and the like.

There is no need to particularly limit the type of polymerization initiator (commonly used inorganic initiators such as water-soluble persulfates and perborates can be used alone or in combination with sulfites, thiosulfates, etc.) as redox initiators. In addition, redox initiation systems such as organic hydroperoxide-ferrous salts, organic hydroperoxide sodium formaldehyde sulfoxylate, benzoyl peroxide, and azobisisobutyronitrile can also be used. Can be used.

The polymer latex obtained by the emulsion polymerization method is coagulated and dried by a known method.

The obtained graft copolymer [■] was mixed with methacrylic resin (I
V) When blending and dispersing K, the most ideal method is melt mixing. Prior to melt-mixing, in addition to the resin composition, stabilizers, lubricants, plasticizers, dyes, pigments, fillers, etc. are added as appropriate, and the mixture is mixed using a V-type blender or Henschel Miki? - Melt kneading at 150 to 300°C using a mixing roll and a screw extruder.

By molding the composition thus obtained using an extrusion molding machine or an injection molding machine, a molded article having excellent weather resistance, transparency, surface gloss, and high low-temperature impact resistance can be obtained.

〔Example〕

Hereinafter, the present invention will be explained in more detail based on Examples.

In addition, in the examples, parts represent parts by weight, and % represents weight %.

Example 1 (1) Production of rubbery copolymer C1l Acrylic acid n-
Butyl (BA) 6-1,3-butadiene (1,3
-BD) 4kg diimpropylbenzene hydroperoxide 20 / potassium tallow fatty acid (TK-1) 120 PN-y sodium uroyl sarcosinate (sarcosinate LN) 80 sodium tabirophosphate 50, P ferrous sulfate
0.5t text rose
30P deionized water 20kg
Among the substances having the above composition ratios, the oxygen contained in the substances other than 1,3-butadiene was replaced with nitrogen, so that the polymerization reaction was not substantially inhibited. The material was then charged into a 401 autoclave and polymerized at 50°C. Polymerization was almost completed in 9 hours, and a rubber latex with a conversion rate of 97% and a particle size of 0.07 μm was obtained.

(Phantom Synthesis of acid group-containing copolymer latex [A] for enlargement) The mixture having the above composition was polymerized at 70°C for 1.5 hours in a 51 glass round bottom flask, and then the mixture was prepared at 70°C. was added dropwise over 1 hour, and stirring was continued for 1 hour to obtain a copolymer latex with a conversion rate of 98%.

The particle size of this was 0.09 μm.

(3) Adjustment of enlarged rubbery polymer [I]′ Rubbery copolymer CI containing 10 kg of polymer solid content While stirring the 601 autoclave containing latex, add latex 152P in the acid group-containing copolymer. After holding for 30 minutes, add 1.5 kl of 10% sodium sulfate aqueous solution. of,
It was added at an internal temperature of 50° C. and held for 15 minutes. The average particle diameter of the obtained enlarged rubbery polymer [I]' was 0.188 μm.

(Production of 4-layer double structure elastic body [1) Polymer solid content of enlarged rubbery copolymer [II]' 10
kg of latex, and 19 units of deionized water, 42/ml of sodium formaldehyde sulfoxylate, and 100ml of sarcosinate LN50J'! Put it in an autoclave, blow in nitrogen gas while stirring, and essentially
After making it free from the influence of oxygen, the internal temperature was raised to 80°C, and 17% of the monomer mixture (C) having the following composition ratio was added to it.
Continuously added for 0 minutes, and after the addition was completed, add 18 more minutes.
Polymerization was continued for 0 minutes to form a latex of double structure acrylic elastic material [■] containing the rubbery copolymer (1) inside the particles and the crosslinked acrylic ester copolymer forming the outer layer. Obtained.

Perbutyl H*2 44M*2 Tertiary butyl hydrocarbon (
Product of NOF Corporation) At this time, the polymerization yield of BA was 97%, and the polymerization yield of ST was 9%.
It was 9.5%.

The particle size of the obtained latex was 0.21 μm.

(5) Multilayer structure graft copolymer (Production of [1) Double structure elastic body obtained above [11] Into the above container containing latex corresponding to 25 to 9 in solid content, sarcosinate LN50J' and After adding 3'klI of deionized water and stirring, the following monomer mixture (Cl) was added continuously over 60 minutes.

Composition of monomer mixture tel (n-O8H) Perbutyl H22.5 heavy The conversion rate of MMA was nearly 100%.

Styrenated phenol 58P and dilaurylthiopropionate 44 were added to the obtained polymer latex 30kliJ.
J',) add Riphenylphosphite 58J', 5
The latex/water was coagulated at 1/2 using 0.25% sulfuric acid water under a temperature condition of 0°C, and further held at 85°C for 5 minutes.

The obtained slurry polymer was washed and dehydrated and heated at 65°C for 3
White multilayered graft copolymer after drying for 6 hours [Seal]
Resin powder was obtained.

This powder resin C114kl? and methyl methacrylate polymer resin (Acrivet (registered trademark) VH; manufactured by Mitsubishi Rayon Co., Ltd.) 6 o'clock, stearic acid monoglyceride 10
P, UV absorber (Tinuvin-P/Sanol LS770
;Ciba Geigy/Sankyo Co., Ltd. products) 20 P/30
/ and mixed with a 20J capacity Henschel mixer,
Next, a 30 mφ twin screw extruder (PC manufactured by Ikegai Tekko Co., Ltd.) was used.
M-30) at a temperature of 230 to 250°C and a rotational speed of 25 Orpm. This pellet-shaped resin was molded using an injection molding machine with a screw set (Nippon Steel New Co., Ltd.; Ankelberg V-17-65 type) at a cylinder temperature of 250°C and an injection pressure (cage pressure) of 50 kg7.2.
So, 11o x 110 x 2 (thickness) tnvt and 70x1
A test of 2.5 x 6.2 (thickness) size was prepared and the evaluation results shown in Table 1 were obtained.

As can be seen from these results, the composition according to the present invention exhibits excellent low-temperature impact resistance, and has good heat stability, heat colorability, and weather resistance.

Examples 2-3, Comparative Examples 1-2 Rubber-like copolymer m constituting the double structure elastic body [ll]
and monomer mixture (constituent ratio of C1 C[l:]/(C))]
An impact-resistant methacrylic resin composition was obtained in exactly the same manner as in Example 1, except for the changes shown in Table 2. Table 2 shows the results of evaluating the physical properties.

Examples 4-5, Comparative Examples 4-5 Impact resistance was obtained in exactly the same manner as in Example 1, except that the monomer components constituting the rubbery copolymer [l] were in the proportions shown in Table 3. A methacrylic resin composition was obtained. The physical property evaluation results are shown in Table 4.

Table 3 Examples 6 to 9, Comparative Examples 6 to 9 Completely the same as Example 1 except that the types and proportions of the monomer components of the crosslinked acrylic ester copolymer tel were changed as shown in Table 5. An impact-resistant methacrylic resin composition was obtained. The physical property evaluation results are shown in Table 6.

Table 5 *7) Acrylonitrile *10) Allyl methacrylate *11) Allyl methacrylate Examples 10-11, Comparative Examples 10-11 The monomer components constituting the monomer mixture (■) are in the proportions shown in Table 7. Except for this, an impact-resistant methacrylic resin composition was obtained in exactly the same manner as in Example 1. The physical property evaluation results are shown in Table 8.

Table 7 *12) Methacrylic acid *13) 2-hydroxyethyl methacrylate Example 12
-15, Comparative Examples 12-14 Acid group-containing copolymer (composition of monomer mixture components constituting Al and acid group-containing copolymer (N latex amount, oxygen Table 9 shows the types and amounts of acid salts.
An impact-resistant methacrylic resin composition was obtained in exactly the same manner as in Example 1, except for the changes shown in . The evaluation results are shown in Table 10.

〔Effect of the invention〕

The composition of the present invention having the above-mentioned structure can be used to form molded products with excellent weather resistance, impact resistance, and surface appearance. It is useful for uses such as covers.

Claims (1)

[Scope of Claims] 1. (a) 20 to 70% by weight of acrylic acid alkyl ester units whose alkyl group has 1 to 8 carbon atoms and 30 to 80% by weight of 1,3-butadiene units, and copolymerizable with these. An emulsion-polymerized rubbery polymer consisting of 0 to 10% by weight of monofunctional or polyfunctional vinyl monomer units [I] Based on 100 parts by weight of the polymer content of the latex, (B) acrylic acid, methacrylate acid, 3 to 40% by weight of at least one unsaturated acid unit selected from the group consisting of itaconic acid, crotonic acid, maleic acid, fumaric acid, cinnamic acid, sorbic acid and p-styrenesulfonic acid, carbon of an alkyl group Emulsifying 35 to 97% by weight of at least one acrylic acid alkyl ester unit having a number of 1 to 12 and 0 to 40% by weight of other copolymerizable units in the same or different composition ratios in one step or in multiple steps. The acid group-containing copolymer (A) in the polymerized polymer latex, and the elements selected from the group of elements belonging to the second and third periods of Groups III to VI in the periodic table of the elements. 0.1 to 5 parts by weight of at least one oxyacid salt (B) selected from alkali metal salts or alkaline earth metal salts of oxyacids, salts of zinc, nickel, and aluminum are added to form a rubber-like product. The copolymer [I] latex is enlarged to have an average particle diameter of 0.12 to 0.4.
μm range, and furthermore, this enlarged rubbery copolymer [
I]' 5 to 75 parts by weight of latex, (c) 69.9 to 89.9% by weight of at least one acrylic acid alkyl ester whose alkyl group has 1 to 8 carbon atoms;
and styrene alone or a mixture of styrene and its derivatives 1
0 to 30% by weight and 0.0 to 30% by weight of a polyfunctional monomer having two or more carbon-carbon double bonds in one molecule that can be copolymerized with this.
Monomer mixture (C) consisting of 1 to 10% by weight 25 to 95
Part by weight was added and polymerized to obtain a double structure elastic body [I
I] In the presence of 100 parts by weight, (d) 80 to 100% by weight of methyl methacrylate, 0 to 20% by weight of at least one acrylic acid alkyl ester having an alkyl group having 1 to 8 carbon atoms, and copolymerized with this. A multilayer structure graft copolymer [III] obtained by polymerizing 5 to 1000 parts by weight of a monomer or a mixture thereof (D) consisting of 0 to 10% by weight of other vinyl monomers having a similar property, and methyl methacrylate. Methacrylic resin [I
An impact-resistant methacrylic resin composition, characterized in that the content of the double-structure elastic body [II] in the mixture is 1 to 50% by weight. 2. A polyfunctional monomer having two or more carbon-carbon double bonds in one copolymerizable molecule in the monomer mixture (C),
It is an ester of at least one unsaturated acid selected from acrylic acid and α,β-substituted acrylic acid and at least one unsaturated alcohol selected from allyl alcohol, methallyl alcohol, and crotyl alcohol. An impact-resistant methacrylic resin composition according to claim 1. 3. A polyfunctional monomer having two or more carbon-carbon double bonds in one copolymerizable molecule in the monomer mixture (C),
Claim 1, characterized in that it is at least one selected from the group consisting of allyl acrylate, allyl methacrylate, allyl cinnamate, and allyl sorbate.
The impact-resistant methacrylic resin composition according to item 1 or 2.