JPH02151614A - Rubber-modified methyl methacrylate resin and thermoplastic resin composition - Google Patents

Abstract

PURPOSE:To obtain the title resin capable of providing impact resistance when it is blended with a thermoplastic resin by emulsion-polymerizing methyl methacrylate alone or a mixture thereof with a specified monomer in the presence of a latex of a rubbery polymer with an average particle diameter of a specified value or larger. CONSTITUTION:A rubber-modified methyl methacrylate resin is prepd. by performing oxidative polymn. of methyl methacrylate (b1) alone or a mixture of methyl methacrylate (b1) and styrene (b2) as the monomer component (B) in the presence of a latex consisting of a rubbery polymer (A) with an average particle diameter of 0.2mum or larger and grafting thereby part of the component B onto the polymer A in such a way that th graft ratio is pref. 20-50wt.%. In this case, the wt. ratio of the components A and B is 30/70-80/20 and the wt. ratio of the components b1 and b2 is usually 100/0-20/80. It is possible to impart impact resistance to a thermoplastic resin with poor impact resistance by blending the title resin therewith.

Description

Detailed Description of the Invention [Industrial Field of Application] The present invention relates to a rubber-modified methyl methacrylate resin that can impart impact resistance to thermoplastic resins that have poor impact resistance, and a rubber-modified methyl methacrylate resin containing the same. The present invention relates to a thermoplastic resin composition with improved impact properties.

[Conventional technology]

Styrene resin, methyl methacrylate resin, methyl methacrylate/styrene copolymer resin, acrylonitrile/styrene copolymer resin, styrene/methacrylic acid copolymer resin,
Thermoplastic resins such as styrene/maleic anhydride copolymer resins are widely used as molding materials in various fields.

However, since these resins have poor impact resistance, a method to improve the impact resistance is generally to introduce diene rubber into the resin. It is used as resin (ABS resin), etc.

As a method for introducing diene rubber, for example, as with HIPS and some ABS resins, a method is used in which monomers or a mixture of monomers are polymerized in the presence of diene rubber to obtain the desired resin at once. Or, as with most ABS resins, on the one hand, a copolymer resin of acrylonitrile and styrene is applied, and on the other hand, a mixture of acrylonitrile and styrene is emulsion polymerized in the presence of a diene system, and both monomers are added to the rubber. One method is to create a resin with a part of the body grafted onto it, and then blend the two into a single resin.

[Problem to be solved by the invention]

In recent years, efforts have been made to add impact resistance to styrene/methacrylic acid copolymer resin (SMAA resin) and styrene/maleic anhydride copolymer resin (SMA resin), which have been increasingly used as heat-resistant resins. In this case, since these resins have hydrophilic carbic acid groups or carbic acid anhydride groups as one of the monomer components, they cannot be used in aqueous systems such as suspension graft polymerization or emulsion graft polymerization as in the case of ABS resins. The use of graft polymerization is not appropriate due to the instability of the polymerization system during polymerization.

[Means to solve the problem]

In view of the current situation, the inventors of the present invention have conducted intensive studies on methods of imparting impact resistance by introducing rubber into resins such as SMAA resin and SMA resin, in which it is difficult to introduce rubber. The present inventors have discovered that impact resistance can be imparted by mixing a rubber-modified methyl methacrylate resin with an average particle diameter of 0.2 μm or more, and have completed the present invention.

That is, in the present invention, a part of the monomer component (B) consisting of methyl methacrylate (b1) or methyl methacrylate (bl) and styrene (b2) is grafted onto the plumy polymer, and a rubber-modified methyl methacrylate resin characterized in that the average particle diameter of the rubbery polymer (A) is 0.2 μm or more, and a thermoplastic resin composition characterized in containing this resin. This is what we provide.

The rubber-modified methyl methacrylate resin used in the present invention has an average particle diameter of 0.2 μm or more, preferably 0.2 μm or more, for example.
．． In the presence of a latex consisting of a rubbery polymer (A) with a diameter of 2 to 0.4 μm, methyl methacrylate (b1) alone or methyl methacrylate (b) and styrene (b2) are added as monomer components (B). ) and a part of the monomer component () is preferably grafted to a graft ratio of 20.
The average particle diameter of the rubbery polymer (A) is 0.2 μm, which is grafted onto the rubbery polymer so that the amount is ~50% by weight.
As mentioned above, preferably a graft copolymer resin having a diameter of 0.2 to 0.4 μm is used.

At this time, the weight ratio (A)/(B) of the rubbery polymer (A) and the monomer component (B) is usually 30/70 to 80/20.
The weight ratio of methyl methacrylate (b) and styrene (b2) is preferably 40/60 to 60/40 (b).
1)/(b2) is usually 10010 to 20/80. Preferably it is 10010 to 40/60.

Examples of the imimetic polymer (A) used here include butadiene homopolymer (BR), styrene/butadiene copolymer (8BR), acrylonitrile/butadiene copolymer (8BR), and acrylonitrile/butadiene copolymer (8BR).
NBR), etc.

Incidentally, the graft ratio is calculated using the following formula.

In addition, the average particle diameter of the rubber-like polymer (A) can be determined by observing an ultra-thin section of the resin using an electron microscope, and calculating the particle diameter of 200 to 500 particles of the rubber-like polymer (A) within the field of view. It was measured and calculated using the following formula.

Average particle diameter = Σn5Di /Σn1D1 However, D in the formula
l is a representative value of the first class when the measured values of the particle diameter are classified into classes with intervals of 0.1 μm, and is an intermediate value between the upper and lower values that distinguish this class from other classes. nl is the number of dispersed particles of the imime polymer (A) belonging to the first class.

The thermoplastic resin for mixing the rubber-modified methyl methacrylate resin is preferably a thermoplastic resin that is compatible with the rubber-modified methyl methacrylate resin, such as methyl methacrylate homopolymer, methyl methacrylate/styrene copolymer, etc. Examples include methyl methacrylate resins such as polymer resins, styrene/methacrylic acid copolymer resins (SMAA resins), styrene/maleic anhydride copolymer resins (SMA resins), vinyl chloride resins (PVC), and the like.

The mixing ratio of these thermoplastic resins and rubber-modified methyl methacrylate resin is not particularly limited, but the rubbery polymer (A) in the thermoplastic resin composition obtained by mixing these
The content is usually 5 to 50%, preferably 10 to 30%
This is a range of % by weight.

〔Example〕

Next, the present invention will be explained in detail with reference to Reference Examples, Examples, and Comparative Examples. In the following, all parts and parts are based on weight unless otherwise specified.

The heat distortion temperature was measured according to ASTM D-648-56, the Izotsu impact strength was measured according to the ASTM D-256-56A method, and the Dapon impact strength was measured using a Dapon impact strength machine newly manufactured by Toyo Seiki Co., Ltd. , a weight of 500.9 was dropped onto a molded product with a thickness of 3 cm under the conditions that the diameter of the striking tip tip was 1/2 inch and the diameter of the striking base cradle was 1/2 inch, and the breaking energy was 50 cm. This is what we sought.

Reference Examples 1 to 2 (Preparation example of SMAA resin (■)) Two types of SMAA resins (1-1) and (1-2) having the compositions shown in Table 1 were prepared by the method described below. It was prepared and used as a partner resin for the rubber-modified methyl methacrylate resin of the present invention.

Reference example 1: 200 in an autoclave with a stirring device of 51
Prepare ON distilled water and further partially saponify it as a suspension stabilizer? Add and dissolve 10 g of ribinyl alcohol and o, osg of sodium lauryl sulfate, then 770 g of styrene.

2309 methacrylic acid, 2.9 di-tart-butyl peroxyhexahydroterephthalate and IJF perbenzoic acid-4ar
T-butyl was sequentially charged, and the temperature was raised to 90° C. while stirring at a rotational speed of 40 Orpm, suspension polymerization was carried out for 10 hours, and the reaction was further continued at 120° C. for 3 hours. The granular polymer thus obtained was washed, dehydrated and dried to obtain SMAA resin (I-1).

Reference Example 2: A granular copolymer, SMAA resin (I-2), was obtained in the same manner as Reference Example 1, except that styrene was changed to 85C1' and methacrylic acid was changed to 1502.

Examples 1 to 4 and Comparative Examples 1 to 2 [Preparation example of rubber-modified methyl methacrylate resin (II)] Using the rubbery polymer and monomer components shown in Table 2, and in the following manner. Various rubber-modified methyl methacrylate resins (II) were prepared using the above method.

Examples 1 to 4 A reactor equipped with a 51 stirrer and purged with nitrogen was heated to 1900F.
After adding 50.9% of pure water and 50.9% of a 20% sodium tyrosinate aqueous solution as an emulsifier, the solid content was 57%.
．． 4% polybutadiene (PBd) latex with an average rubber particle diameter of 0.33 μm was charged in an amount corresponding to the amount of rubbery polymer as shown in Table 2 (Taku: 0.574). Monomer components (1000-(10XPBd(
A))], an amount equivalent to 330 weight of
0.51 of dodecyl mercaptan and 4 Jl of tris(nonylphenyl)phosphite were charged together. Start raising the temperature while blowing in nitrogen gas, and when it reaches 65°C, add 100j' of pure water containing 29 potassium persulfate, and continue to raise the temperature until it reaches 70°C. The remaining amount of the monomer component was added at a constant rate over 2.5 hours, and after the addition was completed, the temperature was maintained at the same temperature for 1.5 hours, and then the temperature was raised to 80°C, and this temperature was maintained for 1 hour. Emulsion polymerization was carried out. After the polymerization was completed, it was coagulated with magnesium sulfate, washed, dehydrated and dried to obtain powdery graft copolymers (If-1) to (II-4).

The average particle diameter of the rubber particles dispersed in the obtained graft copolymer resin was 0.35 μm.

In addition, the graft ratios were all within the range of 30 to 40 inches.

Comparative Examples 1 to 2 Example 1 except that PBd latex with a rubber average particle diameter of 0.16 μm was used and a monomer component was used that was higher than the monomer mixing ratio shown in Table 2. Powdered graft copolymer (n'-i > and (II'
-2) was obtained. The average particle diameter of the rubber particles dispersed in the obtained graft copolymer resin was 0.18 μm. Incidentally, the graft ratios were all within the range of 30 to 40%.

Examples 5-14 and Comparative Examples 3-7 Each SMAA resin obtained in Reference Examples 1-2, commercially available SMA resin, Examples 1-4 and Comparative Examples 1-
Each of the graft copolymer resins obtained in 2.
Blended at the compounding ratio shown in the table, and further added as a stabilizer, octadecyl-3-(3,5-di-tsrt-
After adding 0.2 phr of butyl-4-hydroxyphenyl)-gropionate, the mixture was melt-kneaded in an extruder and pelletized. Next, each pellet was injection molded to obtain each test piece, and the physical properties of each test piece were evaluated. The results are summarized in the same table.

Table 1 [Effects of the Invention] As is clear from the results in Table 3, by blending the rubber-modified methyl methacrylate resin of the present invention with a resin that is compatible with the rubber-modified methyl methacrylate resin, it is possible to eliminate the inherent properties of the other resin. This has the effect of increasing the Izot impact strength without sacrificing physical properties such as ATB.

Agent: Patent Attorney Katsutoshi Takahashi

Claims (1)

[Claims] 1. Methyl methacrylate (b_
1), or a part of the monomer component (B) consisting of methyl methacrylate (b_1) and styrene (b_2) is grafted, and the average particle size of the rubbery polymer (A) is 0.
．． A rubber-modified methyl methacrylate resin characterized by having a diameter of 2 μm or more. 2. Grafting rate of monomer component (B) is 20 to 50% by weight
The resin according to claim 1. 3. The rubber-modified methyl methacrylate resin is obtained by emulsion polymerization of the monomer component (B) in the presence of the latex of the rubbery polymer (A), and (A)/( B
)=30/70~80/20, (b_1)/(b_2)
The resin according to claim 1, wherein the ratio is from 100/0 to 20/80. 4. Grafting rate of monomer component (B) is 20 to 50% by weight
The resin according to claim 3. 5. The resin according to claim 4, wherein the rubbery polymer (A) in the latex has an average particle diameter of 0.2 μm or more. 6. The rubbery polymer (A) is a butadiene homopolymer, a styrene/butadiene copolymer, and acrylonitrile/
The resin according to claim 3, which is one or more rubbery polymers selected from butadiene copolymers. 7. Add methyl methacrylate (b_
1), or a part of the monomer component (B) consisting of methyl methacrylate (b_1) and styrene (b_2) is grafted, and the average particle size of the rubbery polymer (A) is 0.
．． A thermoplastic resin composition comprising a rubber-modified methyl methacrylate resin having a diameter of 2 μm or more. 8. The rubber-modified methyl methacrylate resin is obtained by emulsion polymerization of the monomer component (B) in the presence of the latex of the rubbery polymer (A), and (A)/( B
)=30/70~80/20, (b_1)/(b_2)
The resin composition according to claim 7, wherein the ratio is 100/0 to 20/80. 9. Grafting rate of monomer component (B) is 20 to 50% by weight
The resin composition according to claim 8. 10. The content of the rubbery polymer (A) is 10 to 30% by weight.
The resin composition according to claim 9. 11. The resin composition according to claim 10, which contains a styrene/methacrylic acid copolymer resin, a styrene/maleic anhydride copolymer resin, a methyl methacrylate resin, or a vinyl chloride resin.