JPS61106614A - Production of impact-resistant resin - Google Patents

Abstract

PURPOSE:To obtain a resin excellent in impact resistance, weather resistance, etc., by adding a specified crosslinking agent to an organosiloxane, polymerizing the mixture in the presence of a polyorganosiloxane latex and graft-polymerizing a vinyl monomer with the polymer. CONSTITUTION:100pts.wt. organosiloxane having units of formula I (wherein R<1> is H, methyl, ethyl, propyl or the like and n is 0, 1 or 2), e.g., hexamethyltricyclosiloxane, is mixed with 0.001-10pts.wt. organosiloxane graft crosslinking agent having units of formula II (wherein R<2> is R<1>, R<3> is H or methyl, m is 0, 1 or 2 and p is 1-6). This mixture is polymerized in the pres ence of nearly completely polymerized polyorganosiloxane latex, and a vinyl monomer (e.g., styrene) is graft-polymerized with the obtained polyorganosilo xane particles to obtain the purpose impact-resistant resin.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing an impact-resistant resin, and more specifically, to produce a polyorganosiloxane latex with a controlled particle size, and to achieve high grafting efficiency in the organosiloxane.
The present invention relates to a method for producing an impact-resistant resin obtained by copolymerizing a graft cross-agent having the following properties and then graft polymerizing the graft cross-agent.

It is known that the weather resistance and impact resistance of vinyl thermoplastic polymers can be improved by polyorganosiloxanes containing graft polymerizable functional groups. However, when polyorganosiloxane is used as a resin composition,
It has poor reactivity with other vinyl monomers, making it difficult to form effective chemical bonds. U.S. Pat. No. 3,898,300 describes that the impact strength of styrenic polymers can be improved by polymerizing vinyl monomers in emulsions of vinylyloxane-containing boridimethylsiloxane polymers. in this way,
Depending on the amount of vinyl siloxane in the polyvinyloxane polymer, notched Izot impact strengths of 0.4 to 7 foot bonds are obtained, but as the amount of siloxane relative to the vinyl polymer increases, impact strength decreases. For example 20
% siloxane has an optimum value of about 77-t bond, but drops to 2.17-t e lbs for 49% siloxane. In addition, the gel content of polydimethylsiloxane graft polymers has been measured by the acetate/extraction method.
The maximum ratio of the graft polymer to polydimethylsiloxane was 1.76, and the ratio of monomers involved in grafting among the graft monomers was 10.97%, resulting in extremely poor grafting efficiency. Therefore, vinyl polymer 1
The result is that as the amount of siloxane increases with respect to ``1'', the impact strength ``1'' decreases.

U.S. Pat. No. 4,071,577 describes a method for improving the impact strength of vinyl polymers by replacing vinyl-containing siloxanes with mercaptosiloxanes.

However, the impact strength of vinyl polymers obtained by this method varies greatly depending on the mercapto group content in the polydimethylsiloxane-mercabutoprobil 70 xane copolymer, and the presence of graft polymers via mercapto groups is It has been shown to improve properties.

However, there is no description of the graft ratio, nor is there any description of the rubber particle diameter during emulsion polymerization. In general, as a means of improving impact resistance, it is desirable for the grafting rate to have as high a grafting efficiency as possible in terms of resin production, and for the rubber particle size of the rubber component, the optimum particle size that can exhibit impact resistance is determined by the grafting monomer. In the case of acrylonitrile-styrene graft polymers, it is said to be 0.2 to 0.3μ.

In view of this situation, the present inventors conducted various studies and found that, in order to obtain a polyorganosiloxane rubber, the following steps were taken: - During the emulsion polymerization of siloxane, the particle size of the resulting siloxane rubber and the grafting agent were devised. It has been found that the grafting efficiency of the grafting monomer can be improved and a resin composition having good impact resistance and weather resistance can be obtained.

The present invention relates to an organoorganic compound having a unit represented by the general formula % (in which R1 is a hydrogen atom, a methyl group, an ethyl group, a propyl group, or a phenyl group, and n is a number of 0.1 or 2). 7,100 parts by weight of Siloxa was added with the general formula (where R2 is a hydrogen atom, methyl group, ethyl group, propyl group, or phenyl group, R3 is a hydrogen atom or methyl group, m is Oll or 2, and p is a number from 1 to 6). 0.00
It is characterized by adding ~10 parts by weight of the polyorganosiloxane and polymerizing the polyorganosiloxane latex, at which time the almost completely polymerized polyorganosiloxane latex is allowed to coexist to complete the polymerization, and the resulting polyorganosiloxane particles are graft-polymerized with a vinyl monomer. , a method for producing impact-resistant resin.

According to the method of the present invention, the particle size of the polymer is adjusted to the range where the shock absorption ability is maximized, that is, 0.2 to 0.3μ.
can be controlled. Furthermore, since the grafting efficiency of the polymer is high, the amount of grafting monomer can be suppressed, which is advantageous for exhibiting impact resistance performance.

An important factor that determines the graft structure is the ratio of the polymer grafted to the backbone polymer, that is, the graft ratio, which is an important factor that determines the proportion of the polymer in the polymerized monomer. Vinyl group-containing polyorganosiloxanes or mercapto group-containing polyorganosiloxanes are known as graft cross-agents in conventional methods, but it is difficult to achieve a grafting efficiency of 40% or more no matter which graft cross-agent is used. Met. On the other hand, when using the grafting agent of formula (2), not only a high grafting rate but also a high grafting efficiency, that is, a grafting efficiency of 40% or more can be easily obtained.

When producing the polymer of the present invention, a polyorganosiloxane is produced by first adding a grafting agent of formula (1) to an organosiloxane and polymerizing it in the presence of a polyorganosiloxane latex whose polymerization is almost completed.

Examples of organosiloxane include hexamethyltricyclosiloxane, octamethylte! f,'li Tracyclosiloxane, decamethylpentacyclosiloxane, dodecamethylhexacyclosiloxane, trimethyltriphenyltricyclosiloxane, etc. are used.

The amount of the graft cross-agent of formula (1) to be added is 0.001 to 10 parts by weight, preferably 0.1 to 10 parts by weight, per 100 parts by weight of the organosiloxane.

If the amount of the grafting agent added is less than 0.001 parts by weight, the grafting ratio will be too small to achieve the desired grafting effect. Furthermore, although the graft ratio increases in proportion to the amount of graft cross-over agent added, the degree of polymerization of the graft polymer decreases as the amount of graft cross-over increases, so it is preferably 10 parts by weight or less. However, the formation of graft polymers that are not bonded to polyorganosiloxanes decreases significantly as the amount of graft cross sides increases.

That is, the grafting efficiency can be significantly increased, and if the polymerization conditions are appropriately selected, it is fully possible to obtain a grafting efficiency of 90% or more.

In the polymerization of organosiloxane, the polyorganosiloxane latex, which has been almost completely polymerized, is
0% by weight, preferably 10-30% by weight, and it is necessary to carry out in the presence of this latex.

Polyorganosiloxane latex with almost complete polymerization is prepared by adding the organosiloxane to an aqueous alkylbenzenesulfonic acid solution, adding a cyclic or linear low-molecular-weight siloxane/preferably a terminally hydroxy-blocked polysiloxane, optionally a crosslinking agent, and a compound of formula (1). It can be obtained by adding a cross-agent and homomixing, followed by ordinary emulsion polymerization. This is used as prepolymerized latex.

Examples of cyclic or linear low-molecular siloxanes and crosslinking agents include the general formula % (%) (wherein ? is a hydrogen atom, a methyl group, an ethyl group, a propyl group, or a phenyl group, and q is 0.1 or 2. An organosiloxane having a unit represented by the following formula is used.

A mixed solution of this prepolymerized latex and an aqueous alkylbenzenesulfonic acid solution is prepared, an organosiloxane and a grafting agent of the formula "are added to this mixed solution, and the low molecular weight siloxane is added to the polymer in the polyorganosiloxane latex by homomixing. Large particle size polyorganosiloxane latex can be obtained by swelling and enlarging the particles and then carrying out ordinary emulsion polymerization.

The polymer particle size of the prepolymerized latex is 0.0 μm to 0.16 μm, and the particle size after swelling polymerization is 0.0 μm.
It is 17-0.40μ. The rate of increase in particle size varies depending on the proportion of prepolymerized latex used and the amount of crosslinking agent.

In the production of prepolymerized latexes, copolymerization of grafting agents is not necessarily required.

Furthermore, although such swelling and enlargement polymerization can be carried out repeatedly, the number of repeated polymerizations increases, so it is necessary to contain silicon atoms having three or four functions. This silicon atom acts as a so-called crosslinking agent. A trifunctional crosslinking agent such as methyltrimethoxysilane, phenyltrimethoxysilane, and ethyltriethoxysilane, or a tetrafunctional crosslinking agent such as tetraethoxysilane is added in an amount of 0.0% per 100 parts by weight of the organosiloxane represented by Formula I.
By producing an emulsion using 1 to 10% by weight, gelation of the polyorganosiloxane is caused, and the degree of swelling of the polymer (when the unit weight of the polyorganosiloxane is saturated at 25°C in a toluene solvent, the polyorganosiloxane is Weight percentage of absorbed toluene) from 4 to 30,
Preferably it is adjusted to 5-15.

Measurement of the degree of swelling is carried out in a similar manner. By adding polyorganosiloxane latex to about 3 to 5 times the amount of inopropyl alcohol while stirring, breaking the emulsion and coagulating it)...:, F) yo''
"ty, tr + J-r-via・'"5""" 4 The polymer was washed with water and dried under reduced pressure at 80°C for 10 hours. After drying, approximately 1 g of polymer was accurately weighed and added to approximately 60 g of toluene. The toluene is swollen in the polymer by immersing and leaving at 25°C for 100 hours.Then, the remaining toluene is separated and removed by decantation, weighed accurately, and then heated to 80°C for 100 hours.
Dry under reduced pressure for 6 hours, remove absorbed toluene by evaporation,
Weigh accurately again. The swelling degree is calculated by the following formula.

Emulsion polymerization of organosiloxane can be carried out by a normal emulsion polymerization method, but it is preferable to cool the latex after polymerization and store it at a low temperature to age the latex.

By polymerizing the polyorganosiloxane thus obtained with a graft monomer, a polyorganosiloxane graft polymer can be produced.

This polymerization reaction can be carried out by conventional radical polymerization techniques. As the graft monomer, styrene, α
- Aromatic alkenyl compounds such as methylstyrene and methylenestyrene, methacrylic esters such as methyl methacrylate, ethyl methacrylate and butyl methacrylate, acrylic esters such as methyl acrylate, ethyl acrylate and butyl acrylate, acrylonitrile, methacrylatetril, ethylene, propylene, Conjugated diolefins such as butadiene, isoprene, and chloroprene, vinyl acetate, vinyl chloride, vinylidene chloride, allyl methacrylate, triallyl isocyanate, ethylene dimethacrylate, and mixtures of two or more of these are used.

Preferred monomer proportions include 65-75% by weight styrene and 25-55% by weight acrylonitrile. Various radical polymerization initiators can be used during graft polymerization. Furthermore, when using a certain type of radical polymerization initiator, it is necessary to neutralize the polyorganosiloxane latex acidified with alkylbenzenesulfonic acid to neutrality with an alkali. Examples of alkali include caustic soda, caustic potash, soda carbonate, sodium hydrogen carbonate,
Triethanolamine/triethylamine, etc. are used.

As the radical polymerization initiator, for example, the following compounds are used. Ditertiary butyl peroxide, dicumyl peroxide, tertiary butyl perphthalate, tertiary butyl perbenzoate, tertiary butyl peracetate, ditertiary amyl peroxide, methyl isobutyl ketone peroxide, lauroyl peroxide, cyclohexanone peroxide , 2,5-dimethyl-2,5-ditertiary butyl peroxyhexane, tertiary butyl peroctanoate, tertiary butyl perisobutyrate, tertiary butyl peroxyisopropyl carbonate, diimpropyl peroxydicarbonate Organic peroxides such as cytyl-2,
2'-Azobisisobutyrate, 111'-Azopisci.

Clohexanecarbonitrile, 2-phenylazo-2,
Azo compounds such as 4-dimethyl-4-methquinvaleronitrile, 2-carbamoylazoisobutyronitrile, 2,2'-azobis-2,4-dimethylvaleronitrile, 2,2'-azobisinobutyronitrile, etc. ; and hydroperoxide-ferrous sulfate-glucose-sodium pyrophosphate, hydroperoxide-ferrous sulfate-te*, <
Torose Sodium Pyrophosphate - Sodium Phosphate,
Hydroperoxide - ferrous sulfate - sodium pyrophosphate - sodium phosphate, hydroperoxide - ferrous sulfate - sodium formaldehyde sulfoxylate - ethylenediamine acetate, persulfate - iron hexacyano (M
redox initiators such as potassium persulfate and sodium thiosulfate; copper sulfate; Examples of hydroperoxides include cumene hydroperoxide, tertiary butyl hydroperoxide, diisopropylbenzene hydroperoxide, p-menthane hydroperoxide, 1,1,3.
3-tetramethylbu), ``1 f''do''
-hi*yh"・2,5-dimethy'-"suy-2,5-
Dihydroperoxide etc. are used. As the persulfate, potassium persulfate, ammonium persulfate, etc. are used. Persulfates can also be used alone.

As a graft cross-agent, free radicals are added to mercaptosiloxane and vinyl groups that utilize the continuous addition reaction of graft monomers through chain transfer of mercapto groups, and the generated radicals carry out continuous addition reactions of graft monomers. Although vinyl siloxane, acryloxysiloxane, or methacryloxy 70xane that takes advantage of this fact is considered, it is known that acryloxysiloxane or methacryloxysiloxane of the formula Wataru shows a specifically high grafting efficiency. This is presumed to be because the acryloxy group or methacryloxy group, unlike the vinyl group, receives electron attraction from the adjacent carbonyl group, resulting in extremely high reactivity.

The ratio of the graft monomer to the polyorganosiloxane is such that the amount of polyorganosiloxane is 1~''
Graft polymerization can be carried out at 170% by weight. Preferably 2
It is 0 to 60% by weight.

The graft ratio of the graft polymer is determined as follows. A graft polymer is obtained by adding the graft polymer latex to about 3 to 5 times the amount of methanol while stirring and coagulating the latex. The polymer thus obtained was washed with water and then dried under reduced pressure at 80° C. for 10 hours to remove moisture. After drying, approximately 1 g of polymer is accurately weighed and approximately 50 mJ of acetone is added. This is boiled for about 5 hours at the boiling point of acetone, and the acetone-soluble graft polymer not bonded to the polyorganosiloxane is dissolved in the acetone. After cooling, the mixture is centrifuged at about 10,000 rpm for 1 hour, and then separated by decantation into the polyorganosiloxane-bonded polymer and the a7tone-soluble polymer. The polymer bound to the polyorganosiloxane is washed by further adding acetone and repeating the same centrifugation and decantation operations, and then dried under reduced pressure at 80° C. for 10 hours, and then the weight of the acetone extraction residue is determined. The grafting rate and grafting efficiency are calculated by the following formula.

(Polyorganocloxane weight) This graft polymer latex was coagulated by the usual salting-out coagulation method, and the obtained powder was washed with water and then dried.
It is preferable to shape and pelletize using an extruder. At this time, in order to dilute the siloxane polymer content in the shaped polymer, a polymer such as an acrylonitrile-styrene copolymer may be added and extrusion shaped.

Additionally, additives such as fillers, heat stabilizers, ultraviolet absorbers, and lubricants may be added during extrusion shaping.

The pelletized siloxa/polymer is processed and shaped by conventional means such as compression molding and injection molding. Impact strength was measured on notched specimens according to ASTM-D-256-56 (notches at 45° and 0.1 inch deep).
was produced by injection molding, and its K was measured using an Izod impact tester.

Example 1 3.0 parts by weight of ethyl orthosilicate, 5 parts by weight of r-methacryloxypropylmethyldimethoxy, 1.5 parts by weight of Ran, and 97 parts by weight of octamethyltetracyclosiloxane were mixed, and this was mixed with 2.0 parts by weight of dodecylbenzenesulfonic acid. The mixture was poured into 300 parts by weight of distilled water in which the mixture was dissolved and emulsified by stirring for 3 minutes at 8000 rpm using a homomixer.

This emulsion was transferred to a separable flask equipped with a condenser, a nitrogen inlet, and a stirring blade, and heated at 90° C. for 6 hours while stirring. This latex is referred to as (A). The obtained latex (the polymerization rate of Al was 90.2%, the degree of swelling was 96, and the particle size of the polyorganosiloxane polymer measured by turbidity method was 0.13μ).

Mix 40 parts by weight of latex (A), 1.8 parts by weight of dodecylbenzenesulfonic acid, and 270 parts by weight of distilled water.
Stir to make it homogeneous. This mixture 1; ethyl orthosilicate 2.
A mixture of 7 parts by weight, 0.675 parts by weight of γ-methacryloxypropylmethyldimethoxysilane, and 87.3 parts by weight of octamethyltetracyclosiloxane was added, and the mixture was stirred for 3 minutes at 8000 rpm using a homomixer to emulsify. The mixture was then heated at 90°C for 6 hours to polymerize the siloxane. This latex is referred to as (B).

The polymerization rate of the obtained polyorganosiloxane was 90.8%.
, the degree of swelling is 9.9. The particle size of the polyorganosiloxane polymer measured by turbidity method was 0.20μ.

This polyorganosiloxane latex (Bl.

Adjust the pH to 7.5 with an aqueous sodium carbonate solution, strain IC sodium dodecylbenzenesulfonate 1.0 parts by weight,
700 parts by weight of distilled water and 1.5 parts by weight of potassium persulfate were dissolved and transferred to a separable flask equipped with a condenser, nitrogen inlet and stirrer, and the temperature was raised to 75°C in a nitrogen stream. Next, about 40 parts by weight of a monomer mixture of 50 parts by weight of acrylonitrile and 150 parts by weight of styrene was added using a dropping bottle.
It was added slowly over a period of 10 minutes. After the monomer dropwise addition was completed, the polymerization reaction was carried out for 2 hours, and after the polymerization was substantially completed, the mixture was cooled.

The polymer particle size of the obtained latex was 0.52μ. Add 15 parts by weight of this latex to CaC 2.2.
The polymer was poured into hot water in which H and O were dissolved, and salting out coagulation was performed to separate the polymer. The grafting ratio of the resulting graft polymer, which was thoroughly washed with water, was 8% to 6%, and the polymerization ratio of the graft monomer was 99.7%. This graft polymer powder 60
40% by weight of a copolymer obtained by polymerizing at a monomer charge ratio of 25:75 of acrylonitrile and styrene.
using a single screw extruder with L/D=25,
It was heated to ℃ and shaped to obtain a pellet. This pellet was injection molded into a notched Izot test mold to obtain an Izot test piece. The Izot impact value of this test piece was 49.6 Yu·crn/crn.

Example 2 The type and amount of crosslinking agent used during polymerization of polydimethylsiloxane rubber was investigated.

With the prepolymerization composition and the swelling and swelling polymerization composition being the same, 70 xane rubber was repeatedly polymerized using various crosslinking agents, and the degree of swelling and polymerization rate were measured. The results are shown in Table 1. The polymerization conditions were the same as in Example 1, at 90° C. for 6 hours, and the swelling and swelling polymerization was carried out in the presence of 10% by weight of the latex prepared in the preliminary polymerization. The particle diameter of the obtained latex was measured by a turbidity method, and the results shown in Table 1 were obtained. It is known that there is a correlation between the degree of swelling of the siloxane polymer and the particle size of the latex, and the larger the degree of swelling, the larger the particle size of the latex.

Example 3 Example 1 except that the amount of r-methacryloxypropyldimethoxymethylsilane used as a grafting cross-agent was changed.
Under the same polymerization conditions and monomer amounts, the swelling and swelling polymerization resulted in a weight ratio of 10% by weight of the latex prepared in the prepolymerization.

Next, acrylonitrile and styrene were graft-polymerized. The thus obtained graft polymer and the acrylonitrile-styrene copolymer used in Example 1 were combined in Example 1.
mixed in the same proportions. The relationship between the impact resistance performance and the graft ratio of the obtained resin composition was investigated, and the results shown in Table 2 were obtained.

As the amount of γ-methacryloxypropyldimethoxymethylsilane increases, the grafting rate increases greatly,
Grafting efficiency is also increasing, and it is known that less polymer is involved in grafting. It is also known that the impact resistance converges to a certain value as the grafting ratio increases.

Using Example 4 in Table 2, adjust the pH to 7.8 with an aqueous sodium carbonate solution, then mix 700 parts by weight of distilled water and 2.0 parts by weight of potassium persulfate, and pour the mixture into a dropping bottle, condenser, nitrogen inlet, etc. The mixture was transferred to a separate flask equipped with a stirring blade, and heated to 74°C while flowing nitrogen. A mixture of 200 parts by weight of methyl methacrylate monomer and 0.2 parts by weight of n-octyl mercaptan was slowly added dropwise thereto over about 3 hours. Next, the reaction was maintained for 2 hours, and then cooled, and the graft polymer was evaluated in the same manner as in Example 1. The graft ratio of the obtained graft polymer was 9
The grafting efficiency was 46.81. Also,
At this time, the Izot value with 1/4 inch notch was 11.
It was 6 kg-ctn/cIn.

On the other hand, using 400 parts by weight of the polyorganosiloxane latex prepared in Comparative Example 1, graft polymerization was similarly carried out with a mixture of 200 parts by weight of methyl methacrylate monomer and 0.2 parts by weight of n-octyl mercaptan. When a graft polymer was prepared, the grafting ratio of the polymer was 56.21, and the grafting efficiency was 21.
, 8.1%. 1/4 inch at this time fH I, I, I 1
．． 14.6 on 9-(7n/-Atsue.

Comparative Example 1 In the polymerization trap of polyorganosiloxane, 0.75 parts by weight of vinylsiloxane or 0.75 parts by weight of mercaptosiloxane was used instead of γ-methacryloxypropyldimethoxymethylsila, and the other conditions were as in Example 1. Polydimethylsiloxane was produced in the same manner, and then acrylonitrile and styrene were graft-polymerized. Furthermore, Example 1
The acrylonitrile-styrene copolymer used in Example 1 was blended in the same manner, and the resulting resin composition was extruded and molded. Extrusion, molding, etc. were performed in the same manner as in Example 1. The grafting rate and grafting efficiency of the obtained polymer and the physical properties of the molded product were measured in the third
Shown in the table.

Table 6 Comparative Example 2 A graft polymer was produced using the latex FA obtained in Example 1.

After adjusting 400 parts by weight of latex (A) to pH 7.5 with an aqueous sodium carbonate solution, sodium dodecylbenzenesulfonate, distilled water and potassium persulfate were added in the same manner as in Example 1, followed by 50 parts by weight of acrylonitrile and 150 parts by weight of styrene. The mixture was slowly added dropwise using a dropper bottle over a period of about 4 hours. After the completion of the dropwise addition, the reaction was continued for 2 hours, and then cooled and poured into CaCl,.2H,O water to separate the polymer.

60 parts by weight of this graft polymer powder was mixed with 40 parts by weight of the acrylonitrile-styrene copolymer used in Example 1, and the mixture was shaped to obtain pellets. An Izot test r was prepared from this pellet, and the Izot impact value was determined, and it was found to be as low as 19 Yu·cm/cm.

Claims (1)

[Claims] General formula R^1_nSiO_(_4_-_n_)_/_2( I
) (In the formula, R^1 is a hydrogen atom, a methyl group, an ethyl group, a propyl group, or a phenyl group, and n represents the number of 0, 1 or 2)
For 100 parts by weight of organosiloxane having the unit represented by the general formula ▲ mathematical formula, chemical formula, table, etc. ▼ (II) (wherein R^2 is a hydrogen atom, a methyl group, an ethyl group, a propyl group, or a phenyl group, R^3 is a hydrogen atom or a methyl group,
m is 0, 1 or 2, p is a number from 1 to 6).
001 to 10 parts by weight is added and polymerized, and at this time, almost completely polymerized polyorganosiloxane latex is allowed to coexist to complete the polymerization, and the resulting polyorganosiloxane particles are graft-polymerized with a vinyl monomer. , a method for producing impact-resistant resins.