JPH10152595A - Shock-resistant methacrylic resin composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain the subject resin composition that is excellent in sheet or film-forming properties and processability and can give molding products having no wall thickness deviation and surface roughness and is useful in the optical fields by formulating a specific methacrylic polymer to a specific impact- resistant methacrylic polymer. SOLUTION: (A) 90-99 pts.wt. of a impact-resistant methacrylic resin comprising a multilayer structure polymer prepared by grafting a rubber layer mainly of an alkyl acrylate (M1 ) and the resin layer mainly of an alkyl methacrylate (M2 ) or a multilayer structure polymer prepared by grafting a rubber layer mainly of a conjugated diolefin and the M1 monomer and the resin layer mainly of M2 , and (B) a monomer mixture of 80-100wt.% of a 1-4C alkyl M2 , 0-20wt.% of a 1-8C alkyl M1 and 0-10wt.% of other unsaturated monomers copolymerizable with them are subjected to emulsion polymerization to give the objective resin composition that contains 10-1 pts.wt. of a methacrylic polymer with a viscosity average molecular weight of 300,000-1,000,000.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an impact-resistant methacrylic resin composition, and more particularly to an impact-resistant methacrylic resin composition excellent in injection moldability, sheet moldability, workability, and the like.

[0002]

2. Description of the Related Art Methacrylic resin is colorless and transparent, has a beautiful appearance and excellent weather resistance, and has good moldability, so that louvers, tail lamps, lenses, tableware, electric parts, vehicle parts, optical applications, etc. Although widely used for decoration, miscellaneous goods, signboards, etc., the strength against impact is not always sufficient, and many improvements and modifications have been studied, and it has been commercialized as an impact-resistant methacrylic resin.

However, these commercially available impact-resistant methacrylic resins satisfy the intended impact resistance to some extent, but the fine particles of the multi-layered polymer imparting impact resistance are completely compatible with the surrounding molten resin phase. Instead of dispersing in the form of particles and having an effect on fluidity, injection molding may cause surface defects such as clouding at the gate of the molded product due to molding conditions, mold gate shape, etc. In addition, in sheet molding, film molding or sheet processing, unevenness in the thickness of the sheet may occur and the uniformity may be low, or phenomena such as surface roughness may occur, and it is difficult to obtain a satisfactory product at present. is there.

[0004]

SUMMARY OF THE INVENTION Accordingly, the present invention solves the above-mentioned drawbacks caused by the presence of the multilayer polymer fine particles, provides a good injection-molded product, and can be used in sheet molding, film molding or sheet processing. It is an object of the present invention to provide an impact-resistant methacrylic resin composition which does not cause unevenness in plate thickness, has high uniformity, and can provide a good product without surface roughness.

[0005]

Means for Solving the Problems The present inventors have conducted intensive studies on impact-resistant methacrylic resins excellent in injection moldability, sheet and film moldability and processability, and as a result, have found that specific impact-resistant methacrylic resins have been obtained. By adding and mixing a methacrylic polymer having a high degree of polymerization obtained by emulsion polymerization to the resin,
The inventors have found that the above objects can be achieved, and have completed the present invention.

That is, according to the present invention, there is provided an impact-resistant methacrylic resin [1] represented by the following, which comprises 90 to 99 parts by weight and a methacrylic polymer [2] of 10 to 1 part by weight. This can be achieved by a hydrophilic methacrylic resin composition. Impact-resistant methacrylic resin [1]: mainly composed of a multilayer polymer obtained by grafting a rubber layer mainly composed of alkyl acrylate and a resin layer mainly composed of alkyl methacrylate, and / or mainly composed of conjugated diolefin and alkyl acrylate. An impact-resistant methacrylic resin comprising a multi-layer polymer obtained by grafting a rubber layer and a resin layer mainly composed of alkyl methacrylate. Methacrylic polymer [2]: the alkyl group has 1 to 1 carbon atoms
At least one alkyl methacrylate 80
0 to 100% by weight, 0 to 20% by weight of at least one alkyl acrylate having 1 to 8 carbon atoms in the alkyl group,
And other unsaturated monomers copolymerizable therewith.
A methacrylic polymer having a viscosity average molecular weight of 300,000 to 3,000,000, which is obtained by emulsion polymerization of a monomer mixture consisting of 100% by weight.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail.

The impact-resistant methacrylic resin [1] used in the present invention is a multilayer polymer obtained by grafting a rubber layer mainly composed of alkyl acrylate and a resin layer mainly composed of alkyl methacrylate, obtained by emulsion polymerization. And / or an impact-resistant methacrylic resin comprising a multilayered polymer obtained by grafting a rubber layer mainly composed of a conjugated diolefin and an alkyl acrylate and a resin layer mainly composed of an alkyl methacrylate, and hard methacryl described below. What mixed with resin is mentioned. More specifically, for example, the following are preferably used.

[0009] For example, alkyl acrylate 50 represented by JP-B-54-18298, JP-B-55-27576, and JP-A-55-94917.
９９99.9% by weight, other copolymerizable monoethylenically unsaturated monomers 0-49.9% by weight, crosslinkable monomers and / or graft-linking monomers 0.1-5% by weight. A resin layer mainly composed of an alkyl acrylate and a resin mainly composed of an alkyl methacrylate composed of, for example, 70 to 100% by weight of an alkyl methacrylate and 30 to 0% by weight of another copolymerizable monoethylenically unsaturated monomer. A multi-layer polymer having a particle diameter of about 0.2 to 0.5 μm obtained by emulsion polymerization obtained by grafting layers, or an impact-resistant methacrylic resin obtained by melt-mixing these with a hard methacrylic resin.

For example, conjugated diolefins and alkyl acrylates are 50 to 99.9% by weight, and other copolymerizable monoethylenically unsaturated monomers, such as those disclosed in JP-B-46-18471 and JP-B-55-27576. Mers 0-4
A rubber layer mainly composed of a conjugated diolefin composed of 9.9% by weight, 0.1 to 5% by weight of a crosslinking monomer and / or a graft-linking monomer and an alkyl acrylate; 100% by weight, other copolymerizable monoethylenically unsaturated monomers 30 to 0
% By weight of a resin layer mainly composed of alkyl methacrylate, obtained by emulsion polymerization, and having a particle diameter of about 0.2 to 0.5 μm, or a multilayered polymer or a hard methacrylic resin and melt-mixed. Impact-resistant methacrylic resin.

An impact-resistant methacrylic resin comprising a combination of the above-mentioned multilayer structure polymer or an impact-resistant methacrylic resin obtained by melt-mixing the above-mentioned polymer and a hard methacrylic resin.

The above-mentioned multi-layered polymer generally means a rubber layer /
Resin layer, resin layer / rubber layer / resin layer, rubber layer / resin layer / rubber layer / resin layer, etc., in which the proportion of the rubber layer in the polymer is usually 20 to 70% by weight, preferably Is 30 to 60% by weight. The outermost layer of the multilayer polymer is desirably a resin layer mainly composed of alkyl methacrylate from the viewpoint of melt mixing with a hard methacrylic resin or a methacrylic polymer [2].

The hard methacrylic resin includes:
Any general-purpose methacrylic resin usually used in a molding method such as an injection molding method or an extrusion molding method can be used without any particular limitation, and methyl methacrylate units 80 to 10 can be used.
0% by weight and at least 20 to 0% by weight of an alkyl acrylate unit having 1 to 8 carbon atoms in the alkyl group, and a viscosity average molecular weight of 80,000 to 200,000.
Of these are preferably used. The method for producing the hard methacrylic resin is not particularly limited, and any polymerization method can be adopted, but it is usually produced by emulsion polymerization, suspension polymerization, or the like. The shape is not particularly limited, for example, fine particles having a particle diameter of about 0.1 to 0.5 μm obtained by emulsion polymerization, beads having a particle diameter of about 100 to 800 μm obtained by suspension polymerization, these are extruded. Any material such as the obtained pellet may be used. In general, latex blending is performed in the form of fine particles, and melt blending is performed in the form of beads or pellets.

The mixing amount of the hard methacrylic resin in the impact-resistant methacrylic resin composition of the present invention is 1 to 900 parts by weight based on 100 parts by weight of the impact-resistant methacrylic resin [1] composed of only the above-mentioned multilayer polymer. Parts, preferably 100-600 parts by weight. The method for mixing the hard methacrylic resin is not particularly limited. For example, the hard methacrylic resin is mixed with the above-mentioned impact-resistant methacrylic resin [1], or mixed with the mixture of the impact-resistant methacrylic resin [1] and the methacrylic polymer [2]. Impact-resistant methacrylic resin [1] and / or
Or a method of mixing a part thereof with the methacrylic polymer [2] and then further mixing the remainder, or mixing the impact-resistant methacrylic resin [1], the methacrylic polymer [2] and the hard methacrylic resin together. Can be adopted.

The methacrylic polymer [2], which is another essential component in the impact-resistant methacrylic resin composition of the present invention, comprises at least one alkyl methacrylate having an alkyl group having 1 to 4 carbon atoms. ~ 100% by weight,
Emulsifying a monomer mixture comprising 0 to 20% by weight of at least one alkyl acrylate having 1 to 8 carbon atoms of an alkyl group and 0 to 10% by weight of another unsaturated monomer copolymerizable therewith. Polymerized and has a viscosity average molecular weight of 30
It is necessary that the methacrylic polymer be from 000 to 3,000,000. Methacrylic polymer [2]
Although the details are unclear, it has a function of causing entanglement with a matrix resin forming a molten phase such as a hard methacrylic resin to change the flow behavior, and as an addition ratio thereof, an impact-resistant methacrylic resin [ 1] It is 10 to 1 part by weight, preferably 7 to 2 parts by weight based on 90 to 99 parts by weight. If the amount of the methacrylic polymer is less than 1 part by weight, there is almost no effect of improving the moldability, while if it exceeds 10 parts by weight, the fluidity is undesirably reduced.

Examples of the alkyl methacrylate used for the methacrylic polymer [2] include methyl methacrylate, ethyl methacrylate, butyl methacrylate, and cyclohexyl methacrylate, and methyl methacrylate is particularly preferably used. Examples of the alkyl acrylate include methyl acrylate, ethyl acrylate, n-butyl acrylate, i-butyl acrylate, 2-ethylhexyl acrylate, and the like,
Further, as other unsaturated monomers copolymerizable with these,
Styrene, α-methylstyrene, p-methylstyrene,
Acrylonitrile, methacrylonitrile, and the like,
They are used alone or in combination of two or more.

The viscosity average molecular weight of the methacrylic polymer is from 300,000 to 3,000,000, more preferably from 500,000 to 2,000,000. When the viscosity average molecular weight is less than 300,000, not only the effect of improving the moldability is low but also the fluidity is not improved.
If it exceeds 000, the effect of improving the moldability is undesirably reduced. The methacrylic polymer is not particularly limited as long as it satisfies this condition. For example, it may be a single-layer particle, a multi-layer particle having two or more layers having a changed composition, or a mixture of these particles. You may. This methacrylic polymer is obtained in the form of fine particles by emulsion polymerization, and its particle diameter is preferably from 0.03 to 1 μm, more preferably from 0.05 to 0.5 μm, and the Tg of the methacrylic polymer is preferably (Glass transition temperature) 70-1
It is desirable that the temperature is 20 ° C, more preferably 80 to 110 ° C.

As the impact-resistant methacrylic resin composition of the present invention, a polymer latex or emulsion of the above-mentioned impact-resistant methacrylic resin [1] and methacrylic polymer [2] is uniformly mixed as they are. After that, the coagulated product obtained by coagulation separation and drying by an arbitrary method, a mixture of a polymer latex of each polymer or a coagulated product of an emulsion, or a mixture or fusion of these coagulated products and the hard methacrylic resin It may be a mixture. The impact-resistant methacrylic resin composition thus obtained is used as a molding material used for injection molding or the like in the form of pellets or the like in addition to a solidified or molten mixture, or as it is or in an extruder in the form of a pellet or the like. To be processed into sheets, films, etc. To the impact-resistant methacrylic resin composition, an ultraviolet absorber, an antioxidant, a lubricant, a dye, and the like, which are usually used for a hard methacrylic resin, may be added as necessary within a range that does not hinder the purpose of the present invention. Can be.

[0019]

EXAMPLES Next, the present invention will be described in detail with reference to examples, but the present invention is not limited to these examples.
In the examples, “%” and “parts” are “% by weight”.
And "parts by weight", and the abbreviations of the monomers, polymerization initiators, chain transfer agents and the like used are those in parentheses below.

Methyl methacrylate (MMA), methyl acrylate (MA), ethyl acrylate (EA),
n-butyl acrylate (BA), styrene (ST),
Butadiene (BD), allyl methacrylate (ALM
A), 1,3-butylene glycol dimethacrylate (BG
DMA), potassium persulfate (KPS), n-octyl mercaptan (n-OM)

The evaluation of the physical properties of the resin composition and the like and the evaluation of the moldability in the examples were carried out according to the following methods. (1) Particle size The latex was diluted with pure water to a concentration of 0.1 to 0.2%, and placed in an aluminum tray so as to have a thickness of about 1 mm.
It was dried at 0 ° C., observed with an electron microscope, and the particle size was measured. Electron microscope: Scanning electron microscope manufactured by JEOL Ltd. m
odel JSM-6300F (2) Molecular weight The intrinsic viscosity at 25 ° C. was measured and calculated using chloroform as a solvent.

(3) Glass transition temperature: determined by the equation of Tg Fox. In addition, Tg of each monomer is described in Polymer Handbook / Wiley intersiece.
The value of nce was used. (4) Izod impact strength (with notch) Measured in accordance with ASTM-D256. (5) Heat deformation temperature: Measured according to HDT ASTM-D648 (264 psi). (6) Total light transmittance, haze Measured according to ASTM-D1003 (5 mm thickness).

(7) Evaluation of Molding Processability The moldability and processability of the resin composition are determined by pelletizing the resin composition and molding a 3 mm mirror-finished flat plate using an injection molding machine.
In addition, a 90φ sheet extruder equipped with three mirror rolls
mm extruded plate was manufactured and then evaluated by pushing up after heating.

Example 1 (1) Production of Multilayered Polymer (A-1) Latex 150 parts of ion-exchanged water was placed in a reactor equipped with a reflux condenser.
0.4 parts of sodium stearate and 0.05 parts of sodium lauryl sarcosinate were charged and heated to 80 ° C. while stirring under a nitrogen atmosphere, and then 24 parts of MMA, 1 part of EA, and A
Monomer mixture consisting of 0.05 parts LMA and 1% KP
2.5 parts of an aqueous S solution was charged and reacted for 60 minutes to complete the polymerization. Subsequently, when 5 parts of a 1% KPS aqueous solution was charged, a monomer mixture composed of 41.3 parts of BA, 8.7 parts of ST, and 1 part of ALMA was continuously dropped for 60 minutes, and the whole amount was charged. The polymerization was completed. Then 1%
After charging 2.5 parts of KPS aqueous solution, 24 parts of MMA, M
A1 part and a monomer mixture consisting of n-OM 0.05 part
The whole amount was continuously dropped over 0 minutes, and further maintained for 60 minutes to complete the polymerization to obtain a multilayer polymer (A-1) latex. After the polymerization of each layer was completed, the latex was sampled, and it was confirmed by electron microscopic observation that no new particles were generated and that the sequential polymerization was performed. The particle size of the obtained latex was 0.22 μm. The composition of this latex is shown in Table 1 (A-1).

(2) Production of hard methacrylic resin (B-1) latex 150 parts of ion-exchanged water was placed in a reaction vessel equipped with a reflux condenser.
1.2 parts of sodium stearate and 0.5 parts of sodium lauryl sarcosinate were charged and heated to 75 ° C. while stirring under a nitrogen atmosphere, and then 47 parts of MMA, 3 parts of MA, and n-
OM 0.13 parts monomer mixture and 1% KPS
5 parts of the aqueous solution was charged and reacted for 60 minutes to complete the polymerization. Subsequently, when 5 parts of a 1% KPS aqueous solution was charged, M
After the monomer mixture consisting of 47 parts of MA, 3 parts of MA and 0.13 part of n-OM was continuously dropped for 60 minutes to prepare the whole amount,
Hold for 60 minutes to complete the polymerization. The particle size of the obtained latex was 0.12 μm. The composition of this latex is shown in Table 1 (B-1).

(3) Production of methacrylic polymer (C-1) latex 150 parts of ion-exchanged water was placed in a reaction vessel equipped with a reflux condenser.
After charging 1.2 parts of sodium stearate and 0.5 parts of sodium lauryl sarcosinate, the mixture was heated to 65 ° C. while stirring under a nitrogen atmosphere, and then 25 parts of MMA and 1% KPS
Two parts of the aqueous solution was charged and reacted for 90 minutes to complete the polymerization. Next, when 7.5 parts of a 1% KPS aqueous solution was charged, 75 parts of MMA was continuously added dropwise for 100 minutes, and after charging the whole amount, the mixture was held for 90 minutes to complete the polymerization. The particle size of the obtained latex was 0.15 μm. The composition of the latex is shown in Table 1 (C-1).

Each of the latexes thus obtained was converted into a polymer, and converted into a polymer having a multilayer structure (A-1) 60.
Parts, 35 parts of a hard methacrylic resin (B-1) and 5 parts of a methacrylic polymer (C-1) are uniformly mixed in a latex state, and then a 2% aqueous magnesium sulfate solution is added thereto for salting out and coagulation, followed by washing and drying. Thus, a polymer powder was obtained. 100 parts of the obtained polymer powder and 100 parts of parapet EH beads (manufactured by Kuraray Co., Ltd .: grade for extrusion molding, hereinafter abbreviated as D-1), which is a hard methacrylic resin, are uniformly mixed, and a sheet extruder is used. To obtain an extruded plate, and its physical properties were measured and evaluated. Table 2 shows the results.

Example 2 (1) Production of Multilayer Polymer (A-2) Latex 150 parts of ion-exchanged water was placed in a reaction vessel equipped with a reflux condenser.
After charging 0.2 parts of sodium dioctylsulfosuccinate and heating to 85 ° C. while stirring under a nitrogen atmosphere,
A 3 parts of A, 2 parts of MA, 0.15 part of ALMA and 3.5 parts of a 1% KPS aqueous solution were charged into 6 parts.
The polymerization was completed by reacting for 0 minutes. Subsequently, when 4.5 parts of a 1% KPS aqueous solution was charged, 36.5 parts of BA, ST
A monomer mixture consisting of 8.5 parts and 1 part of ALMA was continuously added dropwise for 60 minutes, and the whole amount was charged, followed by holding for 60 minutes to complete the polymerization. Next, after charging 2 parts of 1% KPS aqueous solution, a monomer mixture composed of 19 parts of MMA, 1 part of MA, and 0.05 part of n-OM was continuously added dropwise over 40 minutes, and the polymerization was completed by further holding for 60 minutes. This gave a multilayer polymer (A-2) latex. After the polymerization of each layer was completed, the latex was sampled, and it was confirmed by electron microscopic observation that no new particles were generated and that the sequential polymerization was performed. The particle size of the obtained latex was 0.15 μm. The composition of this latex is shown in (A-2) of Table 1.

(2) Production of Hard Methacrylic Resin (B-2) Latex 150 parts of ion-exchanged water was placed in a reaction vessel equipped with a reflux condenser.
0.6 parts of sodium dioctylsulfosuccinate was charged and heated to 80 ° C. while stirring under a nitrogen atmosphere.
A18 parts, EA2 parts, n-OM0.05 parts, and 1%
Two parts of the KPS aqueous solution was charged and reacted for 40 minutes to complete the polymerization. Subsequently, when 8 parts of a 1% KPS aqueous solution was charged, a monomer mixture composed of 72 parts of MMA, 8 parts of EA, and 0.2 part of n-OM was continuously dropped for 90 minutes, and the entire amount was charged, followed by polymerization for 60 minutes. Was completed. The particle size of the obtained latex was 0.07 μm. The composition of this latex is shown in Table 1 (B-2).

(3) Production of methacrylic polymer (C-2) latex 150 parts of ion-exchanged water was placed in a reaction vessel equipped with a reflux condenser.
0.5 part of sodium dioctylsulfosuccinate was charged and heated to 75 ° C. while stirring under a nitrogen atmosphere.
A, 27 parts of MA, 3 parts of MA, 0.006 part of n-OM, and 3 parts of 1% KPS aqueous solution
The polymerization was completed by reacting for 0 minutes. Next, when 7 parts of a 1% KPS aqueous solution was charged, 63 parts of MMA, 7 parts of EA,
A monomer mixture consisting of 0.014 parts of n-OM was continuously added dropwise for 100 minutes, and after charging the whole amount, the mixture was maintained for 60 minutes to complete the polymerization. The particle size of the obtained latex is 0.12
μm. The composition of this latex is shown in Table 1 (C-2).

Each of the latexes thus obtained was converted into a polymer, and converted into a polymer (A-2) 80 having a multilayer structure.
Parts, 15 parts of hard methacrylic resin (B-2) and 5 parts of methacrylic high polymer (C-2) were uniformly mixed in a latex state, and then freeze-coagulated at −40 ° C. for 3 hours.
Ice was melted in warm water at 5 ° C., followed by dehydration and drying to obtain a polymer powder. 100 parts of the obtained polymer powder and parapet HR-L, a hard methacrylic resin [manufactured by Kuraray Co., Ltd .: grade for injection molding, hereinafter abbreviated as (D-2)]
100 parts were uniformly mixed and pelletized, and injection molding evaluation and various physical properties were evaluated. Table 2 shows the results.

(Examples 3 to 8) In the same manner as in Example 1, the multi-layered polymers (A-3) to (A-6) having different numbers of layers, compositions and particle diameters, a latex, a hard methacrylic resin ( B-3) A latex and a methacrylic polymer (C-3) latex were obtained. The number of layers of these polymers,
Table 1 shows the composition, particle size, and the like. Except for the mixing ratio of each polymer in the latex blend, the mixing ratio with the hard methacrylic resin at the time of pelletization and sheeting, and the like, as shown in Table 2, the injection molded flat plate and the extruded plate were obtained in the same manner as in Example 1. Was measured and evaluated. The results are shown in Table 2.

(Comparative Examples 1 to 3) The multi-layered polymer latex, the hard methacrylic resin latex and the methacrylic polymer latex in Examples were used, but the mixing ratio of each polymer in the latex blend was determined by the patent of the present invention. When the amount deviated from the scope of the claims, the occurrence of defects was recognized and no satisfactory was obtained. The results are shown in Table 2.

(Comparative Example 4) A methacrylic polymer (C-4) latex having a small molecular weight was obtained in the same manner as in the example, and was blended with the multilayer polymer latex and the hard methacrylic resin latex in the example. However, the generation of defects was recognized and no satisfactory was obtained. The results are shown in Table 2.

[0035]

[Table 1] [In the table, a horizontal line (-) is used to distinguish monomers used to form the same layer, and a hatched line (/) is used to indicate that the layers are different. ]

[0036]

[Table 2]

[0037]

As described above, the impact-resistant methacrylic resin composition of the present invention employs the above-described structure. Therefore, in the injection molding, the gate portion of the molded product depends on the molding conditions, mold gate shape, and the like. There are no surface defects such as cloud
Further, in sheet molding, film molding or sheet processing, a good product with a small thickness deviation and high uniformity and no surface roughness can be provided, and is suitably used in various moldings.

Claims (1)

[Claims] 1. 90 to 99 parts by weight of an impact-resistant methacrylic resin [1] shown below and a methacrylic polymer [2]
An impact-resistant methacrylic resin composition comprising 10 to 1 part by weight. Impact-resistant methacrylic resin [1]: mainly composed of a multilayer polymer obtained by grafting a rubber layer mainly composed of alkyl acrylate and a resin layer mainly composed of alkyl methacrylate, and / or mainly composed of conjugated diolefin and alkyl acrylate. An impact-resistant methacrylic resin comprising a multi-layer polymer obtained by grafting a rubber layer and a resin layer mainly composed of alkyl methacrylate. Methacrylic polymer [2]: the alkyl group has 1 to 1 carbon atoms
At least one alkyl methacrylate 80
0 to 100% by weight, 0 to 20% by weight of at least one alkyl acrylate having 1 to 8 carbon atoms in the alkyl group,
And other unsaturated monomers copolymerizable therewith.
A methacrylic polymer having a viscosity average molecular weight of 300,000 to 3,000,000, which is obtained by emulsion polymerization of a monomer mixture consisting of 100% by weight.