JPS6021180B2 - Acrylonitrile resin composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a highly impact resistant acrylonitrile resin composition with improved weather resistance.

Resins with excellent impact resistance, such as ABS resin obtained by graft polymerizing acrylonitrile and styrene onto polybutazine rubber, polybutadiene rubber, or styrene-butadiene copolymer rubber obtained by graft polymerizing methyl methacrylate and styrene. Molded articles obtained from MBS resins or mixtures of these resins and vinyl chloride resins have the disadvantage that their initial impact strength rapidly decreases when used outdoors. This decrease in impact strength is thought to be due to oxidative deterioration of the rubbery polymer in the resin due to ultraviolet rays from sunlight and oxygen. Therefore, in order to solve the above-mentioned drawbacks, the gene-based rubbery polymer was replaced with a non-gene-based rubbery polymer, such as an alkyl ester polymer of acrylic acid or methacrylic acid.
Attempts have also been made to improve weather resistance by replacing rubber-like polymers that are less susceptible to oxidative deterioration, such as ethylene-propylene copolymers and ethylene-vinyl acetate copolymers.

However, in this case, it is unlikely that the impact resistance will be fully satisfactory. On the other hand, acrylic for molding contains a high proportion of acrylonitrile units.

Nitrile resin is used in food packaging containers and other products because of its excellent gas impermeability, water vapor impermeability, and impact resistance.In addition to the above properties, this resin also has chemical resistance and transparency. Because of its excellent properties, it is expected to be used in applications other than food packaging. In that case, weather resistance is required, especially when used for applications that involve exposure to the outdoors.Although acrylonitrile resins have relatively good flash discoloration resistance, they do not show impact resistance when exposed outdoors. It has the disadvantage that the value decreases rapidly. Therefore, in order to develop a resin with excellent impact resistance and weather resistance, the present inventors focused on acrylonitrile resin, which has excellent impact resistance, and investigated ways to improve the impact resistance of this resin under outdoor exposure. As a result of repeated efforts, the present invention was arrived at.

That is, the present invention uses acrylic.

At least one selected from acrylic acid alkyl esters and methacrylic acid alkyl esters having 60 to 9% by weight of nitrile and an alkyl group having 1 to 6 carbon atoms.
Resin-like copolymer A obtained by polymerizing a monomer mixture consisting of 4% by weight and 0 to 15% by weight of an alkyl methacrylate having an alkyl group having 12 to 18 carbon atoms.
and 30 to 6 parts by weight of a diene rubbery polymer consisting of 50 to 100% by weight of conjugated diene units and 50 to 0% by weight of acrylonitrile units.
At least one selected from acrylic acid alkyl esters and methacrylic acid alkyl esters having 9 weight % and an alkyl group having 1 to 6 carbon atoms and 10 to 7 weight % and an alkyl group having 12 to 18 carbon atoms. A graft copolymer obtained by emulsion polymerization of 80 to 40% by weight of a monomeric polymer consisting of 0 to 15% by weight of an alkyl methacrylate (total amount of 100 parts by weight with the Jen-based rubbery polymer) Combined B with a content of the Jen-based rubbery polymer of 3 to 2
In the resin composition obtained by mixing 30 to 9% by weight of B in the monomer mixture in the presence of an oil-soluble radical initiator,
The present invention relates to a highly impact-resistant acrylonitrile resin composition with improved weather resistance, characterized in that the remaining 70 to 1% by weight is graft-polymerized in the presence of a water-soluble radical initiator. As described above, the graft polymerization in the present invention is carried out in the presence of an oil-soluble radical initiator in an amount of 30 to 9% by weight, preferably 40 to 9% by weight, in the graft monomer mixture, and then the remaining 70 to 9% by weight is carried out in the presence of an oil-soluble radical initiator. 1% by weight, preferably 60-2% by weight, in the presence of a water-moat radical initiator, thereby ensuring that the initial This results in an acrylonitrile resin composition that has excellent not only impact resistance but also inertia resistance, that is, impact resistance under outdoor exposure. This is quite surprising in view of the general fact that resins produced using gene-based rubbery polymers have poor weather resistance. When the amount of monomer used in the first stage graft polymerization is less than 3% by weight, the initial impact strength is low and no improvement in weather resistance is observed, whereas when it exceeds 9% by weight, Although the initial impact strength is good, no improvement in weather resistance is observed. The amount of acrylonitrile used in the production of resinous copolymer A in the present invention is from 60 to 9% by weight, preferably from 65 to 85% by weight in the monomer mixture.

If the content is less than 6% by weight, the impact resistance will be poor, and if it exceeds 9% by weight, the melt molding processability will deteriorate, making it impractical.

In addition, the acrylic acid alkyl ester and methacrylic acid alkyl ester having an alkyl group having 1 to 6 carbon atoms used in the production of A include methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, Examples include methyl methacrylate, ethyl methacrylate, propyl methacrylate and butyl methacrylate.

If the amount used is less than 1% by weight in the monomer polymer, moldability will be poor, and if it exceeds 4% by weight, impact resistance will be poor.
The preferred amount used is 15-35% by weight. Carbon number 12 to 18 used as necessary in the production of A and B
Examples of the methacrylic acid alkyl ester having 2 alkyl groups include lauryl methacrylate and stearyl methacrylate. These monomers can be used for the purpose of imparting water resistance and alkano resistance. The amount used is 0-15% by weight, preferably 0-1% by weight.
It is. When the amount exceeds 15% by weight, the effect of improving water resistance and alcohol resistance reaches saturation, and furthermore, when used in the production of A, a peeling phenomenon is observed in the melt-molded product, which is not preferable.

Although A can be produced by any conventional suspension polymerization or emulsion polymerization method, it is preferable to use an emulsion polymerization method.

As a polymerization initiator, commonly used organic or inorganic peroxides such as potassium persulfate, ammonium persulfate, hydrogen peroxide, benzo, ylperoxide, and Yuichisharybutyl peroxypivalate, azobis Azo free radical generators such as isobutyronitrile and redox initiators that are a combination of a water-soluble peroxide and a reducing agent are used. Further, as the emulsifier, a surfactant such as an alkali metal salt of a higher fatty acid, rosin acid or alkylbenzenesulfonic acid; an alkali metal salt of a sulfate ester or a phosphate ester of a higher aliphatic alcohol is used. The polymerization temperature is 0 to 10,000. Further, during polymerization, a method of adding the monomer mixture and other components continuously or intermittently can also be adopted. The diene rubbery polymer used in the production of graft copolymer B in the present invention has 5 conjugated diene units such as butadiene or isoprene.
0-10% by weight, preferably 70-10% by weight and 50-0% by weight of acrylonitrile units, preferably 30-0% by weight
% by weight and is usually prepared by emulsion polymerization.

If the amount of acrylonitrile units exceeds 5% by weight, the impact resistance of the resulting resin composition will decrease, which is not preferred. In addition, as the Jen-based rubbery polymer, one having a low glass transition point is preferable in order to improve the impact resistance of the resin composition, especially at low temperatures. The amount of acrylonitrile to be grafted onto the rubbery polymer is from 30 to 9% by weight, preferably from 35 to 8% by weight based on the total grafting monomers.
It is 5% by weight.

If the amount used exceeds 9% by weight, the impact resistance will decrease and the molded product will become more yellowish. When the amount is less than 3% by weight, impact resistance decreases.

Moreover, as the acrylic acid alkyl ester and methacrylic acid alkyl ester having an alkyl group having 1 to 6 carbon atoms, those similar to those used in the production of A above can be used.

The amount used is from 10 to 7% by weight, preferably from 15 to 65% by weight. If it is less than 1% by weight or more than 7% by weight, the impact resistance will be poor.

Graft polymerization in the presence of a gene-based rubbery polymer can be carried out according to an emulsion polymerization method.

The ratio of the rubbery polymer to the polymer mixture to be graft-polymerized thereto is 20/80 to 60/4, or 40/60 to 60/40 (parts by weight). If the proportion of the rubbery polymer exceeds 6 parts by weight, the impact resistance and surface gloss of the molded article will be poor, and if it is less than 2 parts by weight, the impact resistance will become poor. The oil-soluble radical initiators used in the first stage of graft polymerization include benzoyl peroxide, octanoyl peroxide, lauroyl peroxide, 3,5,5-trimethylhexanoyl peroxide, 2,4-dichlorobenzoyl/ -Oxide, Cumene Hydro/Gu-Oxide,
Diisopropylbenzene hydro/gu oxide, P
-Menthanhide.

Peroxide, organic peroxides such as diisopropyl peroxydicarbonate, di-2-ethylhexyl peroxydicarbonate, t-butyl peroxypivalate, t-butyl peroxymaleic acid, azobisisobutyro Nitrile, 2,2-azobis(2,4-
Azo compounds such as dimethylvaleronitrile) and 2,2-azobis(4-methoxy2,4-dimethylvaleronitrile) are mentioned. In addition, water-soluble radical initiators used in the second stage include persulfates such as potassium persulfate and ammonium persulfate, inorganic peroxides such as hydrogen peroxide, and these inorganic peroxides and reducing agents. Water-soluble redox initiators, etc., which are made by combining the above are used.

Further, as the emulsifier, the same emulsifier as used in the production of A above can be used.

The method of adding a single polymer during graft polymerization is as follows:
A method in which the entire amount is added at the start of the first stage polymerization, a method in which it is added in two parts at the start of the first stage polymerization and a method in which it is added in two parts at the start of the second stage polymerization, and Although a method of continuously or intermittently adding the remaining monomer at different times may be proposed, any method may be employed as long as it satisfies the requirements defined in the present invention.

The mixing ratio of A and B is such that the amount of the rubbery polymer in the total amount of A and B is 3 to 2% by weight, preferably 5 to 2% by weight.

Even if the amount of the Jen-based rubbery polymer exceeds 2% by weight, the impact strength reaches saturation. The method of mixing both may be either dry blending or latex blending. In addition,
When the resin composition of the present invention is prepared to have the same composition only by graft polymerization without mixing A and B, impact resistance and processability (flow characteristics due to increase in melt viscosity during molding) ) is poor, and furthermore, there is a concomitant drawback that yellowing of the molded product increases.

The melt-molded product of the resin composition of the present invention prepared in this way or a composite obtained by laminating the resin composition of the present invention on other plastics such as vinyl chloride resin or ABS resin and molding is a food product. In addition to packaging containers, it is especially effective as molded products used outdoors. The present invention will be explained below by way of examples.

Note that parts and percentages in the examples are based on weight unless otherwise specified. Example 1 Production of resinous copolymer 100 parts of the monomeric polymer shown in Table 1, 1.5 parts of n-dodecyl mercaptan, 0.8 parts of sodium lauryl sulfate,
Anhydrous sodium pyrophosphate 0.2%, potassium persulfate 0
．． 08 parts and 20 parts of water were placed in an autoclave and polymerized at 560 for 1 hour under a nitrogen atmosphere (see Table 1 for polymerization conversion), resulting in a good resin-like copolymer with no aggregates. A-1 and A-2 were obtained.

Table 1 2 - [11 Production of diene-based rubbery polymer latex All of the following polymerization recipes except CHP were charged into an autoclave, and the temperature of the reaction system was adjusted to 5°C under a nitrogen atmosphere. was added to the system and the reaction was completed while feeding for 2 hours (polymerization conversion rate 97%) to obtain a highly stable acrylonitrile-butadiene rubber-like copolymer latex.

The rubbery copolymer in this latex was found to be uniform particles with an average particle size of 0.1 mm, as observed by electron microscopy. This rubbery copolymer latex was used to prepare a two-legged graft copolymer. Polymerization prescription (parts) Acrylonitrile 151,3-butadiene 85t-dodecylmercaptan 0.4 Sodium lauryl sulfate 1.5 Sodium carbonate
0.2 kyumene hydroperoxide (CHP) 0.08 ferrous sulfate heptahydrate
0.01 dextrose
0.05 Ethylenediaminetetraacetic acid disodium monohydride 0
．． 02 Wed 20
02-[2} Preparation of Graft Copolymer B The monomers shown in Table 2, the polymerization initiator, and the acrylonitrile-butadiene rubber-like copolymer prepared with 2-m. 3 parts, sodium lauryl sulfate 0.
Part 8, anhydrous pi.

A graft copolymer latex with good stability was obtained by charging 0.2 parts of sodium phosphate and 60 parts of water into an autoclave and polymerizing in accordance with the stated conditions under a nitrogen atmosphere. . Table 2 * Comparative Sample 3 Production of resin composition and evaluation of physical properties Resin-like copolymer A produced in 1 and 2-■ above, respectively
The latex and graft copolymer B latex were mixed in the combinations shown in Table 3 so that the content of the rubbery copolymer in the resulting resin composition was 1% by weight, and the mixed latex was mixed with 0%. . After coagulating with a 4% aluminum sulfate aqueous solution and salting the polymer, washing in a separate furnace with water,
A white powdery polymer was obtained by drying for 8 hours.

This white powdery polymer was melt-molded to prepare a notched test piece based on the ASTM D-256 test method.

This test piece was coated with a weather-resistant coating using Sunshine Carbon.
The impact values of those exposed for 40 cycles and 80 field hours using a meter, and those that were not exposed, were measured using a Wizod impact tester, and the quality of weather resistance was examined. The results are shown in Table 3. Table 3 × Comparative example
The resin compositions of the present invention (experiment numbers 4, 6, 7, and 8) have high initial impact resistance values, and have film resistance, that is, weather resistance.
High impact resistance value retention after exposure to O-meter.

On the other hand, a composition containing a graft copolymer prepared using only a water-soluble initiator (experiment number 1) and a composition containing a water-soluble initiator in the first stage and an oil-soluble initiator in the second stage were used. The compositions containing the graft copolymers (Experiment Nos. 5 and 9) prepared using each of these had low initial impact resistance values and poor stiffness resistance. The composition containing the graft copolymer prepared using only an oil-soluble initiator (Experiment No. 2) had a high initial impact resistance value, but
Poor weather resistance. Furthermore, the composition containing a graft copolymer prepared by using an oil-soluble initiator and a water-lacquer initiator in combination from the start of polymerization (Experiment No. 3) had poor stool resistance. In addition, no difference was observed in the transparency of each sample before and after exposure using a weather-o-meter when observed with the naked eye.

Claims (1)

[Claims] 1 60-90% by weight of acrylonitrile and 1-6 carbon atoms
A monomer consisting of 10 to 40% by weight of at least one selected from acrylic acid alkyl esters and methacrylic acid alkyl esters having an alkyl group of In the presence of resinous copolymer A obtained by polymerizing a polymer mixture and 20 to 60 parts by weight of a diene-based rubbery polymer consisting of 50 to 100% by weight of conjugated diene units and 50 to 0% by weight of acrylonitrile units. 30 to 90% by weight of acrylonitrile and at least one selected from acrylic acid alkyl esters and methacrylic acid alkyl esters having an alkyl group having 1 to 6 carbon atoms, 10 to 7
80 to 40 parts by weight of a monomer mixture consisting of 0% by weight and 0 to 15% by weight of an alkyl methacrylate having an alkyl group having 12 to 18 carbon atoms (total amount of 100 parts by weight with the diene rubber-like polymer) Part) is mixed with graft copolymer B obtained by emulsion polymerization so that the content of the diene rubbery polymer is 3 to 20% by weight, in which B is , in the monomer mixture, 30-9
0% by weight is graft-polymerized in the presence of an oil-soluble radical initiator, and the remaining 70 to 10% by weight is graft-polymerized in the presence of a water-soluble radical initiator. An improved high impact resistant acrylonitrile resin composition. 2. The acrylonitrile resin composition according to claim 1, wherein the entire monomer mixture is added to the polymerization system during graft polymerization in the presence of an oil-soluble radical initiator. 3 The monomer mixture is divided into two parts and added to both polymerization systems during graft polymerization in the presence of an oil-soluble radical initiator and graft polymerization in the presence of a water-soluble radical initiator, respectively. Acrylonitrile resin composition. 4. The acrylonitrile resin composition according to claim 1, wherein the oil-soluble radical initiator is an organic peroxide or an azo compound. 5. The acrylonitrile resin composition according to claim 1, wherein the water-soluble radical initiator is an inorganic peroxide or a water-soluble redox initiator.