JPH0645737B2 - Thermoplastic resin composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of use] The present invention relates to an impact-resistant resin composition having excellent transparency and weather resistance, and extremely excellent moldability.

[Conventional technology]

Methacrylic resin is used in large quantities commercially because of its elegant appearance and excellent weather resistance, but it is inferior in impact resistance.
There may be a problem when handling.

For this reason, various methods have been proposed for introducing rubber to improve impact resistance. However, in most cases, the graceful appearance and weather resistance of the methacrylic resin are impaired, making it difficult to put to practical use.

For example, as a method for improving impact resistance without relatively impairing transparency, a method disclosed in Japanese Examined Patent Publication (Kokoku) No. 45-26111 is known. In this method, an elastic body of its constituent component is butadiene-butyl acrylate copolymer. Since it is a united product, it has good transparency in the early stage of production, but when it is used outdoors, it quickly becomes cloudy or cracked, and the transparency and impact resistance deteriorate.

Also, Japanese Patent Publication No. 54-18298 proposes a method of blending a methacrylic resin with a graft copolymer having an acrylic ester as a main component to obtain a resin composition excellent in transparency, weather resistance and impact resistance. Has been.

[Problems to be solved by the invention]

Conventionally proposed various impact resistant methacrylic resins show excellent transparency and impact resistance when injection-molded as a molding material, but there is a strong demand for further improvement in moldability, and T-die etc. When it is made into a film by using, there is a defect that a thin product cannot be formed or thickness unevenness easily occurs.

[Means for solving problems]

In view of the above facts, the present inventors, without impairing the properties of the methacrylic resin, that is, colorless transparency and weather resistance,
As a result of earnestly examining a resin composition having excellent moldability,
The present inventors have found that excellent moldability can be obtained by blending a specific copolymer and have reached the present invention.

That is, the gist of the present invention is to include 0.1 to 20 parts by weight of a thermoplastic polymer [I] shown below, 5 to 99.9 parts by weight of a rubber-containing polymer [II], and a thermoplastic polymer [I]. III)
0 to 94.9 parts by weight, [I], [II], [II
The total amount of I] is 100 parts by weight in the thermoplastic resin composition.

[I] Thermoplastic polymer 50 to 100% by weight of methyl methacrylate and 0 to 50% by weight of at least one other vinyl monomer copolymerizable therewith, and the reduced viscosity of the polymer (polymer 0.1 g was dissolved in 100 ml of chloroform and measured at 25 ° C.) was 0.1.
A thermoplastic polymer of 2 to 1.2 / g.

[II] Rubber-containing polymer 50 to 99.9% by weight of alkyl acrylate, 0 to 40% by weight of other copolymerizable vinyl monomer, and 0.1 to 10% by weight of copolymerizable crosslinkable monomer % Of a methacrylic acid ester in the presence of 100 parts by weight of an elastic copolymer obtained by polymerizing a monomer mixture of 100% by weight, and 0 to 50% by weight of a vinyl-based monomer copolymerizable therewith. A rubber-containing polymer obtained by polymerizing 10 to 1000 parts by weight of a monomer consisting of

[III] Thermoplastic Polymer From 50 to 100% by weight of a methacrylic acid ester having an alkyl group having 1 to 4 carbon atoms and 0 to 50% by weight of at least one other vinyl monomer copolymerizable therewith. Becomes
Reduced viscosity of the polymer (0.1 g of the polymer was added to chloroform 10
A thermoplastic polymer which is dissolved in 0 ml and measured at 25 ° C.) is 0.1 / g or less.

In the present invention, when the thermoplastic polymer [I] is less than 0.1 part by weight in the thermoplastic resin composition of the present invention, sufficient moldability cannot be obtained, and the thermoplastic polymer [I] is not obtained. Is more than 20 parts by weight, the viscosity of the resin composition becomes too high and moldability deteriorates, which is not preferable.

The thermoplastic polymer [I] in the present invention comprises 50 to 100% by weight of methyl methacrylate and 0 to 50% by weight of another vinyl-based monomer copolymerizable therewith, and the reduced viscosity ( 0.1 part by weight is dissolved in 100 ml of chloroform and measured at 25 ° C.) is 0.2 to 1.2 / g.

In the thermoplastic polymer [I] used in the present invention, examples of vinyl monomers copolymerizable with methyl methacrylate include acrylic acid alkyl esters, methacrylic acid alkyl esters, aromatic vinyl compounds and vinyl cyan compounds. Can be used.

The alkyl acrylate is preferably one having an alkyl group having 2 to 10 carbon atoms, for example, ethyl acrylate, propyl acrylate, n-butyl acrylate, isobutyl acrylate, hexyl acrylate, octyl acrylate and acrylic acid. 2-ethylhexyl and the like can be mentioned.

As the methacrylic acid alkyl ester, those having an alkyl group having 2 to 4 carbon atoms can be used, and ethyl methacrylate, propyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, tert-butyl methacrylate and the like can be used. Is mentioned.

Further, as the aromatic vinyl compound, styrene, α-substituted styrene, nucleus-substituted styrene and derivatives thereof, for example, α
-Methylstyrene, chlorostyrene, vinyltoluene and the like.

Further, examples of the vinyl cyan compound include acrylonitrile and methacrylonitrile.

As the polymerization initiator, an inorganic initiator such as a common persulfate or an organic peroxide, or an azo compound or the like may be used alone,
Alternatively, the above compound and a sulfite, a hydrogen sulfite, a thiosulfate, a first metal salt, sodium formaldehyde sulfoxylate and the like can be combined and used as a redox initiator. Preferred persulfates as the initiator are sodium persulfate, potassium persulfate, ammonium persulfate and the like, and organic peroxides include t-butyl hydroperoxide, cumene hydroperoxide, benzoyl peroxide, lauroyl peroxide and the like. is there.

The molecular weight and molecular weight distribution of the copolymer are important factors for the processability imparting effect, and a suitable chain transfer agent can be used depending on the purpose.

The polymerization can be carried out at a temperature equal to or higher than the decomposition temperature of the initiator under ordinary emulsion polymerization conditions, and the polymerization can be carried out in one stage or multiple stages depending on the purpose.

The copolymer can be usually recovered by powdering after coagulation by salting out or acidification, and then by washing with water, or by spray-drying or freeze-drying.

The rubber-containing polymer [II] in the present invention has a function of imparting excellent impact resistance and elongation to a resin composition, and has a multi-layered graft copolymer having an alkyl acrylate ester as a main component of rubber. It is united.

The rubber-containing polymer [II] in the present invention comprises 50 to 99.9% by weight of alkyl acrylate, 0 to 50% by weight of another copolymerizable vinyl monomer, and 0 to 50% of a copolymerizable crosslinkable monomer. 1 to 10% by weight of a monomer or a mixture of monomers is (co) polymerized in at least one step to obtain an elastic body,
Then, in the presence of 100 parts by weight of the elastic body, a monomer or a monomer mixture consisting of 50 to 100% by weight of a methacrylic acid ester and 0 to 50% by weight of another vinylic monomer copolymerizable therewith. It is obtained by polymerizing ˜1000 parts by weight in at least one stage.

If the amount of the alkyl acrylate ester in the elastic body is less than 50% by weight, the impact resistance improving effect is small, which is not preferable. If the amount of the crosslinkable monomer in the elastic body is less than 0.1% by weight, a sufficient crosslinking effect cannot be obtained, and if it exceeds 10% by weight, the crosslinking will be too strong and the elastic properties of the elastic body will be impaired. It is not preferable because the impact resistance is lowered.

As the acrylic acid alkyl ester that can be used here,
An alkyl acrylate whose alkyl group has 1 to 8 carbon atoms, of which butyl acrylate and acrylic acid-
2-Ethylhexyl and the like are particularly preferable. When obtaining the elastic copolymer, less than 50% by weight of another copolymerizable vinyl monomer can be copolymerized. As the other copolymerizable vinyl-based monomer used here, methacrylic acid alkyl esters such as methyl methacrylate, butyl methacrylate and cyclohexyl methacrylate, styrene, acrylonitrile and the like are preferable. When polymerizing a monomer or monomer mixture containing an acrylic acid alkyl ester as a main component, it is necessary to crosslink this (co) polymer. The crosslinking agent monomer used is not particularly limited,
Preferably ethylene glycol methacrylate, ethylene glycol diacrylate, 1,3-butylene dimethacrylate, 1,4-butanediol diacrylate, allyl acrylate, allyl methacrylate, diallyl phthalate, triallyl cyanurate, triallyl isocyanurate, Examples thereof include divinylbenzene, allyl sorbate, diallyl maleate, trimethylolpropane acrylate, and allyl cinnamate, and these can be used alone or in combination.

As the monomer to be grafted, a monomer or a mixture of monomers containing methacrylic acid ester as a main component is added in an amount of 10 to 100 parts by weight of an elastic body containing acrylate ester as a main component.
1000 parts by weight can be polymerized in at least one stage, and a preferred range is 20 parts by weight to 200 parts by weight.
If the amount to be grafted is 10 parts by weight or less, it is difficult to recover the rubber-containing polymer as a good powder, and if the amount to be grafted exceeds 500 parts by weight, the desired impact resistance cannot be obtained. Absent.

The ratio of the rubber-containing polymer [II] is the thermoplastic resin [I],
It is 5 to 99.9 parts by weight with respect to 100 parts by weight in total with [III]. When the proportion of the rubber-containing polymer [II] is less than 5 parts by weight, impact resistance and film elongation are lowered.

Examples of the methacrylic acid ester copolymerizable monomer include methacrylic acid alkyl esters such as ethyl methacrylate, butyl methacrylate, and 2-ethylhexyl methacrylate, methyl acrylate, ethyl acrylate, butyl acrylate, acrylic acid- Acrylic acid alkyl esters such as 2-ethylhexyl, styrene and its derivatives, acrylonitrile, methacrylic acid, acrylic acid, itaconic acid, maleic acid, fumaric acid, vinyltoluene, and the like, and preferably methyl acrylate, ethyl acrylate, etc. Acrylic acid alkyl esters.

The rubber-containing polymer [II] in the present invention is preferably obtained by an emulsion polymerization method, and the same catalyst, emulsifier and chain transfer agent as those used for obtaining the thermoplastic polymer [I] should be used. In addition, it can be recovered as a powder in the same manner as the thermoplastic polymer [I].

The thermoplastic polymer [III] in the present invention has 1 to 1 carbon atoms.
It is a polymer obtained by polymerizing a monomer containing at least 50% by weight of a methacrylic acid ester having an alkyl group of 4, and methyl methacrylate is most preferable. If the methacrylic acid ester is 50% by weight or less, the film
The moldability during sheet molding is poor, and the transparency of the resulting film is also poor.

Further, if the reduced viscosity exceeds 0.1 / g, the fluidity deteriorates, which is not preferable. The method for polymerizing the thermoplastic polymer [II] is not particularly limited, and various known methods such as suspension polymerization and emulsion polymerization may be applied.

The present invention relates to the thermoplastic polymer [I] thus obtained,
A resin composition comprising [III] and a rubber-containing polymer [II], which is a resin composition excellent in molding processability without impairing the original properties of methacrylic resin.

The thermoplastic resin composition of the present invention is obtained by melt-kneading the thermoplastic polymers [I] and [III] and the rubber-containing polymer [II]. Prior to melt-kneading, a predetermined amount of each, together with stabilizers, lubricants, dyes, pigments, fillers, etc., if necessary, using a powder (pellet) mixer such as a V-type blender or a Hensiel mixer, is sufficiently uniform. It is necessary that they are mixed, and after that, they are melt-kneaded at 160 to 280 ° C. using a Banbury mixer, a plaftograph, a mixing roll, a screw type extruder or the like.

By molding the composition of the present invention thus obtained using an injection molding machine or an extrusion molding machine, transparency, surface gloss,
A molded product having excellent impact resistance can be obtained.

Further, the composition of the present invention can be made into a film-like molded product having excellent transparency, weather resistance and surface gloss by adopting a melt extrusion method such as a T-die method, an inflation method and a calender method. . The preferred temperature for carrying out melt extrusion is 180 to 260 ° C.

The film-shaped molded product obtained from the composition of the present invention can be improved in weather resistance and decorative effect by adhering or laminating to a steel plate, a plastic sheet, wood or the like by utilizing its excellent physical properties. .

Hereinafter, the present invention will be described in more detail with reference to Examples. In the examples, "part" means "part by weight" and "%" means "% by weight".

The total light transmittance, tear strength, impact strength, and film forming property in the following examples were determined by the following methods.

Total light transmittance; in accordance with ASTM D1003-61,
It was measured by an integral haze meter.

Tear strength; based on JIS P-8116, notch 2
Calculated by the Elemendorff method of mm.

Impact strength: A Dupont falling weight test was performed to determine the 50% breaking height.

Film film-forming property: The thickness was measured at 10 points in the film width direction, and the thickness at which the film could be formed to the thinnest was found within a range in which the thickness unevenness did not exceed 20% of the average value.

[Examples 1 to 5 and Comparative Examples 1 to 3] a) Production of thermoplastic resin [I] 200 parts of ion-exchanged water substituted with nitrogen was charged into a reaction vessel, and 1 part of emulsifier potassium oleate and 0.3 parts of potassium persulfate were used. The department was set up. Subsequently, 40 parts of methyl methacrylate, 10 parts of n-butyl acrylate, n-octylmethylcaptan of 0.
005 parts were charged and the polymerization was completed by stirring for 3 hours at 65 ° C. under a nitrogen atmosphere. Followed by methyl methacrylate 4
A monomer mixture consisting of 8 parts and 2 parts of n-butyl acrylate was added dropwise over 2 hours, and after the completion of the addition, the mixture was maintained for 2 hours to complete the polymerization. The obtained latex was added to a 0.25% sulfuric acid aqueous solution, and the polymer was acid-deposited, dehydrated, washed with water and dried,
The polymer was recovered in powder form. The reduced viscosity ηsp / C of the obtained copolymer was 0.38 / g.

b) Production of rubber-containing polymer [II] The following proportions of raw materials were charged into a reaction vessel, and the polymerization was completed while stirring at 50 ° C. for 4 hours in a nitrogen atmosphere to obtain an elastic latex.

Butyl acrylate (BA) 77 parts Styrene 22.7 parts Allyl methacrylate 0.3 parts Sodium dioctylsulfosuccinate 2.0 parts Deionized water 300 parts Potassium persulfate 0.3 parts Disodium phosphate dodecahydrate 5 parts Sodium hydrogen phosphate dihydrate 0.3 parts 100 parts by weight of this elastic latex (as solid content) was placed in a reaction vessel, and nitrogen substitution was carried out while stirring.
After raising the temperature to 0 ° C. and adding an aqueous solution containing 0.125 parts of sodium formaldehyde sulfoxylate and 2 parts of water, while maintaining the temperature at 80 ° C., methyl methacrylate 60 was added.
Parts, 0.05 parts of n-octyl mercaptan and 0.125 parts of t-butyl hydroperoxide.
After dropping over a period of time, the mixture was kept for 2 hours to complete the polymerization.

The obtained copolymer latex was added to a 3% saline solution, and after salting out, dehydration, washing with water and washing were carried out to obtain a rubber-containing polymer [II] in a powder form.

c) Manufacture of Molded Article Methyl methacrylate / methyl acrylate copolymer [[] which is the thermoplastic polymer [I] and the rubber-containing polymer [II] and the thermoplastic polymer [III] obtained as described above. Methyl methacrylate / methyl acrylate = 98/2, ηsp / C
= 0.06 / g] were mixed in various ratios shown in Table 1 with a Henschel mixer. Then, using a 40 mmφ screw type extruder (L / D = 26), the cylinder temperature is 200 to 2
The mixture was melt-kneaded at 60 ° C and a die temperature of 250 ° C to form a pellet.

The obtained pellet was dried at 80 ° C. for a whole day and night, and film-forming was performed using a T-die. Table 1 shows the physical properties and moldability of the obtained film. The physical properties of the film were measured for each having a thickness of 0.1 mm. It is understood from Table 1 that the film thin film formability is significantly improved by mixing the thermoplastic polymer [I] in a specific amount.

[Examples 6 to 8 and Comparative Example 4] a) Production of thermoplastic polymer [I] 200 parts of ion-exchanged water substituted with nitrogen was charged into a reaction vessel, and 1.5 parts of potassium oleate and 0 potassium persulfate were used as emulsifiers. .3 parts were prepared. Then, methyl methacrylate 80
Parts, 20 parts of ethyl acrylate and 0.005 parts of n-octyl mercaptan were charged and stirred at 65 ° C. for 3 hours under a nitrogen atmosphere to complete the polymerization (Example 6). Similarly, n-
Example 7 in which the amount of octyl mercaptan was changed,
8 and Comparative Example 4.

A rubber-containing polymer [II] and a thermoplastic polymer [III] similar to those in Example 1 and the above various thermoplastic polymers [I] were obtained in the same manner as in Example 1 to obtain a film. Table 2 shows the physical properties and film-forming properties of the obtained film. From Table 2, it is understood that when the reduced viscosity of the thermoplastic polymer [I] is less than 0.1 / g, the film moldability is deteriorated.

[Examples 9 to 12, Comparative Example 5] a) Production of rubber-containing polymer [II] In the same manner as in Example 1-b), elastic latices containing an acrylic ester as a main component were obtained. When graft-polymerizing a monomer mixture consisting of 85% methyl methacrylate, 14% styrene, and 1% ethyl acrylate onto this elastic latex, the amount of grafting to 100 parts (as solid content) of the elastic latex is changed, Various rubber-containing polymers [II] were obtained. The physical properties and moldability of a film obtained by operating the above rubber-containing polymer [II] and the same thermoplastic polymer [I] and / or [III] as in Example 1 in the same manner as in Example 1 are shown. 3 shows. It can be seen that when the amount of grafting is less than 10 parts, good powder cannot be obtained, and when the amount of grafting exceeds 500 parts, the impact resistance and elongation of the film deteriorate.

[Effects of the Invention] As described in detail below, the present invention can provide a resin composition having excellent moldability without impairing the original excellent properties of methacrylic acid resin.

Claims (1)

[Claims] 1. A thermoplastic polymer [I] 0.
1 to 20 parts by weight, a rubber-containing polymer [II] 5 to 99.9 parts by weight, and a thermoplastic polymer [III] 0 to 94.9 parts by weight, and comprises [I], [II] and [III]. A thermoplastic resin composition having a total of 100 parts by weight. [I] Thermoplastic polymer 50 to 100% by weight of methyl methacrylate and 0 to 50% by weight of at least one other vinyl monomer copolymerizable therewith, and the reduced viscosity of the polymer (polymer 0.1 g was dissolved in 100 ml of chloroform and measured at 25 ° C.) was 0.1.
A thermoplastic polymer of 2 to 1.2 / g. [II] Rubber-containing polymer 50 to 99.9% by weight of acrylic acid acrylic ester, 0 to 40% by weight of other copolymerizable vinyl monomer, and 0.1 to 10% by weight of copolymerizable crosslinkable monomer % Of a methacrylic acid ester in the presence of 100 parts by weight of an elastic copolymer obtained by polymerizing a monomer mixture of 100% by weight, and 0 to 50% by weight of a vinyl-based monomer copolymerizable therewith. A rubber-containing polymer obtained by polymerizing 10 to 1000 parts by weight of a monomer consisting of [III] Thermoplastic Polymer From 50 to 100% by weight of a methacrylic acid ester having an alkyl group having 1 to 4 carbon atoms and 0 to 50% by weight of at least one other vinyl monomer copolymerizable therewith. Becomes
Reduced viscosity of the polymer (0.1 g of the polymer was added to chloroform 10
A thermoplastic polymer which is dissolved in 0 ml and measured at 25 ° C.) is 0.1 / g or less.