JPS5863712A - Thermoplastic resin having excellent impact strength - Google Patents

Abstract

PURPOSE:To prepare the titled resin having excellent processability and surface properties, by copolymerizing styrene, acrylonitrile, methyl methacrylate, etc. in the presence of an acrylic rubber subjected to the particle growth treatment with a specific acid group-containing copolymer latex. CONSTITUTION:The objective resin is prepared by polymerizing (A) 93-30pts.wt. (as solid) of a monomer mixture composed of 30-100(wt)% styrene, acrylonitrile and/or methyl methacrylate and 0-30% other monomer in the presence of (B) 7-70pts.wt. of a grown rubber latex having particle diameter of >=0.2mu and obtained by adding (i) 0.1-5pts.wt. of an acid group-containing copolymer latex derived from 3-30% (meth) acrylic acid, itaconic acid and/or crotonic acid, 97-35% 1-12C alkyl acrylate and 0-48% other copolymerizable monomer to (ii) 100pts.wt. of an acrylic rubber latex obtained by copolymerizing 100- 50wt% 2-10C alkyl acrylate, 0-50% other copolymerizable functional monomer, and a polyfunctional monomer.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a new thermoplastic resin having excellent impact resistance.

Impact-resistant resins such as ABS resin and high-impact polystyrene are usually obtained by graft polymerizing styrene, acrylonitrile, methyl methacrylate, and other monomers to a rubber component, but the composition and structure of the graft copolymer, the rubber The content, polymerization method, etc. greatly influence the physical properties of the final composition. In particular, when graft polymerizing rubber components using emulsion polymerization, it is a widely known fact that the particle size of the base rubber component controls the impact resistance and processability of the final composition. The larger the size, the better the impact resistance and processability of the resulting resin.

Therefore, attempts have been made to make the rubber particle size as large as possible, and various proposals have been made so far.

The present applicant has also previously discovered that diene rubber can be enlarged with a copolymer latex consisting of an unsaturated acid monomer and an alkyl acrylate, and in the presence of the obtained enlarged rubber latex, styrene, acrylonitrile and methyl methacrylate are added. We have proposed a resin composition with good impact resistance obtained by polymerizing a monomer containing at least one selected from the group, but as a result of further studies, we have arrived at the present invention.

The present invention provides 100 to 50 by weight of an alkyl arylate whose alkyl group has 2 to 10 carbon atoms, 1 to 50 by weight of a monofunctional monomer copolymerizable therewith, and a polyfunctional monomer copolymerizable with these. Acrylic rubber (4) latex obtained by polymerizing monomers consisting of 0 to 5 weight - 100 weight is
(as solid content), acrylic acid, methacrylic acid,
6 to 30% by weight of at least one kind of monomer imported from the world of itaconic acid and crotonic acid, with an alkyl group having 1 to 1 carbon atoms.
At least one alkyl acrylate of 12 97-35
Weight - and other copolymerizable monomers 0 to 48 weight -
acid group-containing monomer obtained by polymerizing a monomer consisting of
7 to 70 parts by weight of enlarged rubber latex having a particle size of at least 0.2 μ (liid type 30 to 100% by weight of at least one monomer selected from the group consisting of styrene, acrylonitrile and methyl methacrylate (as a fraction) and a monomer having a group of 0 It is a thermoplastic resin with excellent impact resistance and surface properties obtained by polymerizing 95 to 60 parts by weight of a monomer mixture consisting of ~50 parts by weight.

As the rubber component), alkyl acrylate homopolymer or 50% or more alkyl acrylate and 50%
- Copolymers consisting of vinyl monomers copolymerizable with the following copolymers are included, and it is also possible to use a crosslinking agent in combination, and these can be easily obtained by commonly known emulsion polymerization. There are no particular restrictions on the catalyst, emulsifier, etc., and the particle size thereof is 104 to 12 microns.

Copolymers containing acid group-containing monomers such as acrylic acid, methacrylic acid, itaconic acid and crotonic acid are then used to thicken the rubber latex.

It is essential for this copolymer (i) to contain an acid group-containing monomer and an acrylate, and the acrylate is selected from at least one type of purkyl acrylate whose alkyl group has 1 to 12 carbon atoms. .

Even if a monomer such as methacrylate, styrene, or acryl-tetranitrile is used in place of acrylate, no effect is observed. is irt O The above-mentioned basic idea M single cap is used in the range of 6 to 30 weight, and if it is less than 3, the feeding power for enlargement is small, and on the contrary, if it exceeds 60 is undesirable because it is too strong and produces particles larger than 1 μm.

In addition, the optimum size of the acid group-containing monomer varies depending on the degree of hydrophilicity of the acrylate used, and if the acrylate is not hydrophilic, it will become enlarged in the ik range where the amount of acid group-containing monomer is small. On the other hand, when the amount of acid group-containing monomer increases, the latex becomes broken, which is undesirable.On the other hand, when the hydrophilicity of acrylate is low, thickening occurs in the region where the amount of acid group-containing monomer is low. It is less effective and will not be effective unless the amount of acid group-containing monomer fox is greater than the root bark. For example, in the case of methyl acrylate and ethyl acrylate, which are highly hydrophilic acrylates, the amount of acid group-containing monomer is 5.
-10-, whereas in the case of butyl acrylate and 2-ethylhexyl acrylate, which are hydrophobic alkyl acrylates in which the carbon me of the alkyl group is 4 or more, the amount of acid group content is 15-20. Optimal when you are fluent. Note that when a highly hydrophilic acrylate is used, even if the amount of acid group content polymer is 5 to 109G, the system tends to become unstable, and currents (coarse particles) are therefore likely to occur.511 points On the other hand, when hydrophobic acrylates such as those mentioned above are used, the threads do not become unstable and uniform enlarged particles can often be obtained.

As acid group content monomers or similar monomers,
In addition to the above, there are cinnamic acid, maleic anhydride, buty/tricarboxylic acid, etc., but their use is not practical because of their small enlargement ability.

The acid group-containing copolymer) is added to the base rubber (4) in the form of latex.
) Latex Ic is added. At this time, when an inorganic electrolyte, preferably an inorganic salt, particularly a neutral inorganic salt, is added, the particle size of the base rubber can be enlarged very efficiently and stably.

The amount of the acid group-containing copolymer φ) latex to be added is based on the amount, and is particularly preferably 1lk5 to 3fi lid part. Mata Kuroiso Electrolysis'
When X is added, the amount added is [105 to 4 parts by weight, particularly preferably 11 to 1 part by weight] per 100 parts by weight of the base rubber.
L parts is sufficient, and by adding a small amount of 5iC, the base rubber can be enlarged efficiently in a short time, and the stability of the obtained large particle diameter rubber latex can be greatly improved.

Inorganic IE electrolytes include KCL, NaCL, and Naps.
Inorganic salts known in Tong Tang, such as O, etc., can be used.

It is also possible to add this inorganic electrolyte in advance during the polymerization of the base rubber latex, and it has the same effect as when it is added at the time of enlargement.

When carrying out the enlargement treatment of the present invention, it is preferable to keep the pH of the base rubber latex at 7 or higher. When the pH value is in the acidic range, even if an acid group-containing copolymer () latex is added, the enlargement efficiency is low, and the composition targeted by the present invention cannot be advantageously produced. For example, polybutyl acrylate rubber latex polymerized with sodium octylsulfosuccinate as an emulsifier and potassium persulfate as a catalyst has a pa of 2 to 3, but even if an acid group-containing polymer latex is added to this latex, No enlargement occurs at all. However, if a small amount of alkali such as potassium hydroxide is added to raise the pH to 7 or more, rubber with large particle size can be easily obtained.

Adjusting the pH of the latex (to this base rubber) to 7 or higher may be carried out during the polymerization of this base rubber, or may be carried out separately before the enlargement treatment.

Rubber latte 7/Sufu that was enlarged in this way
In the presence of 70 parts by weight, styrene, acrylonitrile,
By polymerizing monomers mainly composed of methyl methacrylate, the desired impact-resistant pulp can be obtained.

If the rubber content is less than 7% by weight, it has low impact resistance and is of no practical value, and if it exceeds 70% by weight, the fluidity and processability will be poor and therefore undesirable. The preferred rubber content is F110 to F25 by weight. Examples of monomers to be grafted onto the rubber latex include styrene alone, methyl methacrylate alone, styrene-acrylonitrile monomer mixture, styrene-acrylic acid ester monomer mixture, methyl methacrylate-acrylonitrile monomer mixture, and methyl methacrylate-monomer mixture. Examples include acrylic ester monomer mixtures, acrylonitrile-acrylic ester monomer mixtures, and monomer mixtures of three or more of these monomers.

In this emulsion graft polymerization, commonly known emulsifiers and catalysts are used, and there are no particular restrictions on their quality or addition.

The obtained graft polymer has a rubber content in the graft polymer having rubber as the base material, which is not in the range of 7 to 70 weight US, but the final content of the pre-nod ridge is L7.
It is preferably in the range of ~70% by weight. Examples of rubber-free resins used at this time include polystyrene, polymethyl methacrylate, As4 resin, polyvinyl chloride, and polycarbonate.

When graft polymerizing the enlarged rubber, the graft monomer may be added all at once, it may be added in portions, it may be added continuously, or each monomer may be graft polymerized individually in stages. .

Known antioxidants, lubricants, colorants, fillers, etc. can be added to the obtained graft polymer or graft-blend polymer.

In the following examples, parts and parts mean parts by weight and weight S, respectively.

Example 1 ■ Production of acrylic rubber (person-1) latex Ion-exchanged water 200s Olein-plated potassium 50 parts Methyl methacrylate
4 Styrene 1211 Acrylonitrile 128 Acrylic acid n
-Butyl 72 parts triallyl isocyanurate
Q. 5 parts potassium persulfate
A mixture consisting of 6 parts of the above composition was polymerized at 70° C. for 4 hours. The polymerization rate was 96%, the semi-uniform particle size of the resulting elastic material was 0.09μ, and the pH was 91.

■ Synthesis of acid group-containing copolymer (B-1) latex for enlargement n-butyl acrylate 85 parts Methacrylic #
15 parts dioctyl sodium sulfosuccinate α5 parts cumene hydroperoxide
(L41S sodium formaldehyde sulfoxylate α 5s ion exchange water 200
Using a mixture having the above composition, polymerization was carried out at 70° C. for 4 hours. The resulting latex was converted (14 was 98%, pH was 2.
It was 4.

(A-1) Put 100 parts of latex (solid content) into a container and add 2.0 parts of latex (B-1) to it while stirring.
iiim min) was added at room temperature.

After stirring this latex for 30 minutes, and after that, the semi-average particle diameter was determined by subjecting the latex to 5 days of testing. The results are shown in Table-1.

(2) Synthesis of graft polymer (G-1) The enlarged latex obtained by stirring for 50 minutes was immediately subjected to graft polymerization at 80 DEG C. for 4 hours according to the following composition to synthesize a graft polymer.

Enlarged rubber (hard silkworm content) 60 parts methyl methacrylate 8 parts acrylonitrile
8 parts styrene 24ml
-Octyl mercaptan α0411 Potassium persulfate α2 parts Olei/potassium acid tOs■ Evaluation of various physical properties 50 parts of the graft polymer obtained in the above (Ml) and MA/AN
/St = 20 /20/40 (to) Suspended particles SO@ which were separately produced using a monomer body temperature metal material were blended 4
The acrylic rubber in the resin composition was closed with a gold lid, 5G.

Furthermore, 11 parts of barium stearate 1s1 Tinuvin P (ultraviolet a absorbent manufactured by Geigy) was added to this resin composition and pelletized using an extruder. Using this pellet, each woodcutter-tested specimen was prepared by injection molding, and various physical properties were evaluated. These results are shown in Table 1. Note that the notched Izot strength values in Table 1 are determined by ASTM-1)-254, the melt index (MI) is determined by # of polymer flowing out in 10 minutes at 200°C and a load of 5, and the surface gloss is determined by 1.
Formed into a flat plate with a thickness of A inch, ASTM-D5
23-62TK based on the angle of incidence and reflection of 60 degrees, the 'ili surface glossiness was determined. These evaluation methods are the same for the following Examples and Comparative Examples.

Comparative Example 1 Acrylic rubber (
A-2) was synthesized by the following method.

Put 200 parts of ion-exchanged water into the synthesis reaction container of (Person-2) and heat it to 80℃.
After raising the temperature, potassium oleate t5s and potassium persulfate α6s were added, and the monomer mixture of (A-1) and -1 (excluding potassium oleate and potassium persulfate) was continuously heated for 2 hours and 30 minutes. was injected.

The average particle size of the acrylic rubber latex thus obtained was 150μ.

Using this rubber, a graft polymer was prepared in the same manner as in G-1, and the same amount of suspended particles as blended in Example 1 was blended. In the case of the example resin composition, when injection molding etc. are carried out, K,
Cat 1: A rainbow-colored striped pattern appeared near the gate of the structure.
In the present invention, such red color does not occur at all! 111
It was 1.

Example 2 The B-1) latex was added in varying amounts to 100 m (-1 minute) of the (Mu-1) latex of Example 1, and the same evaluation as in Example 1 was performed thereafter.

Comparative Example 2 For comparison, (A-1) A similar evaluation was carried out when the latex was graft-polymerized without enlarging it. In (A-1) of Example 6, Example 9111, the composition was changed as follows. Otherwise, acrylic rubber (A-2) latex was produced in exactly the same manner.

Ion exchange water 20 parts (is n-butyl acrylate 76 parts acrylonitrile
9s Styrene 15 parts Triallyl cyanurate 1 part Sodium dioctyl sulfosuccinate Tos Potassium persulfate α9 parts Polymerization rate 97%, average particle size α08
fi and pHFi were 2.4.

(A-2) 100 parts of rubber latex was mixed with caustic soda to change the pH of the latex, and (B-1)
After adding 20 parts of latex and enlarging it, Example 1
We prepared a graft polymer in the same manner as above and attempted to evaluate its physical properties.

Claims (1)

[Claims] Alkyl acrylate whose alkyl group has 2 to 10 carbon atoms 100 to 50 by weight, a monofunctional monomer copolymerizable with this θ to 50 by weight, and a polyfunctional monomer copolymerizable with these 0 Acrylic rubber obtained by polymerizing monomers consisting of ~5% by weight CA) 100 parts by weight (as the national content) of latex, a compound selected from acrylic acid, methacrylic acid, itaconic acid, and crotonic acid. At least one monomer 3 to 50% by weight, at least one alkyl acrylate whose alkyl group has 1 to 12 carbon atoms 97 to 55]IL
Acid group-containing copolymer 03 obtained by polymerizing monomers consisting of 48% by weight and other copolymerizable monomers
) Latex α 1 to 5 parts by weight (as solid content) and required!
! from the group of styrene, acrylonitrile and methyl methacrylate in the presence of 7 to 70 parts by weight (as solids) of a thickened rubber latex with a particle size of at least 12 μ obtained by adding 105 to 4 parts by weight of an inorganic electrolyte. At least one selected monomer SO~100 weight value and CH copolymerizable with it, = C (monomer θ~
Thermoplastic #4N0 with excellent impact resistance obtained by polymerizing 95 to 60 parts by weight of a monomer mixture ##4N0 consisting of 50 parts by weight