JPS5839860B2 - Antistatic resin composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides an electrical resistor comprising 10 to 50% by weight of a monomer having 4 to 500 alkylene oxide groups and one or more monomers selected from conjugated dienes and acrylic esters. This invention relates to a composition of a graft copolymer obtained by graft copolymerizing a vinyl monomer or a vinylidene monomer to a rubber base polymer having a low ratio, and a thermoplastic resin that is compatible with the graft copolymer. be.

In general, plastics have a high electrical resistivity and are easily charged with electricity due to friction and peeling, which can attract dirt and dust and cause various problems in the fields of molded products, sheets, films, fibers, etc. such as damaging the appearance. ing.

Studies have been conducted to impart antistatic properties to such plastics that are easily charged, and they can be broadly classified into the following types.

1. Internal kneading method of antistatic agent 2. Surface coating method of antistatic agent (surfactant) 3. Surface coating method of silicone compound 4. Chemical modification method of plastic structure The internal kneading method has not succeeded in permanently preventing static electricity, and if the antistatic agent present on the surface is removed by washing with water, friction, or other means, the antistatic effect is lost.

Exceptionally, internally kneaded antistatic agents that are wash-resistant have been put into practical use for polyethylene, polypropylene, polyvinyl chloride, etc., but they require time to recover their antistatic effect after washing, and antistatic agents are difficult to prevent. If the agent bleeds to the surface too much, there are disadvantages such as dirt and dust sticking together, transparency, and the fact that it has not been put to practical use in terms of coin size.

Furthermore, a step of adding an antistatic agent is required.

In the method of applying a surfactant to the surface, the antistatic effect is drastically reduced by washing.

The method of applying a silicon-based compound to the surface has an excellent antistatic effect and can be expected to have a semi-permanent antistatic effect, but it has poor work efficiency and is disadvantageous in terms of cost.

A method of chemically modifying the structure of plastics is to introduce hydrophilic groups into the plastics through polymerization or other methods, but in general it is necessary to contain a fairly large amount of hydrophilic groups in order to exhibit an antistatic effect. Yes, moisture absorption adversely affects mechanical properties and other physical properties.

The inventors of the present invention have conducted extensive research with the aim of creating a resin with permanent antistatic properties that will not deteriorate when washed. A mixture of a graft copolymer obtained by graft polymerizing monomers and a resin compatible with the graft copolymer has a permanent antistatic effect, and has a rubber backbone polymer of 4 to 500%. It was discovered that a copolymer consisting of 10 to 50% by weight of a monomer having alkylene oxide groups and 50 to 90% by weight of one or more monomers selected from conjugated dienes and acrylic esters is suitable. , completed the present invention.

The antistatic properties of the resin composition according to the present invention can of course be improved by adding an antistatic agent.

Since the polyalkylene oxide group is chemically bonded to the rubber backbone polymer, the antistatic properties will not deteriorate even under severe cleaning conditions.

Further, since there is no need to hydrophilically modify the matrix phase (the phase consisting of the branched polymer phase and the thermoplastic resin), even if the rubber phase absorbs moisture, it will hardly affect the overall physical properties.

Furthermore, by appropriately controlling the particle size, amount added, refractive index, etc. of the rubber phase, it is possible to create a resin composition that is transparent and has high impact resistance.

Regarding the method of producing a resin composition having antistatic properties by copolymerizing a monomer containing polyalkylene oxide, for example, JP-A-48-18521, JP-A-51-29526,
It is described in Japanese Patent Application Laid-Open No. 50-78642.

However, all of these are random copolymers of monomers containing polyalkylene oxide, or mixtures of these and other polymers, and if the monomer containing polyalkylene oxide is contained in a small amount, the effect will be small; It has the disadvantage that it becomes hygroscopic when used for.

On the other hand, in the present invention, it is necessary that the monomer having a polyalkylene oxide group exists in the rubber backbone polymer, and the phases of the rubber backbone polymer are in a bridged state with each other in the sheet polymer phase during processing. It is presumed that the charge mainly diffuses and attenuates through this rubber base polymer phase, thereby exerting the antistatic effect.

In the case of the present invention, even if the moisture absorption rate of the rubber trunk polymer phase in the plate increases, the water absorption rate of the branch polymer phase hardly changes, so there is an advantage that almost no decrease in mechanical strength or heat resistance is observed.

As mentioned above, it is necessary that the monomer having an alkylene oxide group be present in the rubber backbone polymer.

If this is present simply as a component of a random copolymer rather than a rubber backbone polymer, a polymer having excellent antistatic properties as in the present invention cannot be obtained with the same amount added.

The rubber backbone polymer of the present invention contains 50 to 90% by weight of one or more monomers selected from conjugated dienes and acrylic esters and 10 to 50% by weight of a monomer having 4 to 500 alkylene oxide groups. % and, if necessary, one or more copolymerizable vinyl monomers or vinylidene monomers from 0 to 49% by weight.

As the monomer having 4 to 500 alkylene oxide groups, monomers having structures shown in the following formulas (I) and (II) are used.

R1, R2, R3 are hydrogen or an alkyl group having 1 to 4 carbon atoms, X is hydrogen or an alkyl group having 1 to 9 carbon atoms, m and n are 4
≦m +n≦5000 Of course, it is also possible to use similar monomers having polyalkylene oxide groups and capable of lowering the bulk electrical resistivity of the rubber backbone polymer.

4 to 500 alkylene oxide groups are required,
It is more preferable that the number is 9 to 50.

If the number of alkylene oxide groups is less than 4, it will be difficult to impart antistatic properties, and if it is more than 500, it will be difficult to dissolve in water or monomers during polymerization, and the polymerizability will also be poor.

Furthermore, if the monomer having a polyalkylene oxide group is less than 10% by weight of the rubber backbone polymer, antistatic properties cannot be imparted.

Moreover, if it exceeds 50% by weight, difficulties arise in polymerizability and manufacturability.

As the copolymerizable vinyl monomer or vinylidene monomer used in the rubber backbone polymer, known monomers can be used.

For example, methacrylic acid alkyl ester, acrylic acid,
Methacrylic acid, acrylamide, methacrylamide, vinyl acetate, unsaturated nitrile, aromatic vinyl, alkyl vinyl ether, alkyl vinyl ketone, 2-hydroxyethyl (meth)acrylic acid ester, diaheptane acrylamide, vinyl chloride, vinylidene chloride, itaconic acid , itaconic acid alkyl ester, isobutyne, 2-acid phosphoxyethyl methacrylate, 3-chloro-
1 such as 2-acid phosphoxyethyl methacrylate
More than one species of monomer can be used.

As the copolymerizable vinyl monomer or vinylidene monomer, a highly polar monomer such as acrylonitrile or a monomer containing an ionic substituent such as a sulfonic acid group, a lino acid group, a carboxylic acid group, etc. If you select , the antistatic property will further improve.

Furthermore, if necessary, a polyfunctional monomer having two or more of one or more of vinyl groups, 1,3-butadienyl groups, acrylic groups, methacrylic groups, and allyl groups may also be used as a crosslinking agent in the rubber backbone polymer. I can do it.

In particular, a polyfunctional monomer having 4 to 500 polyalkylene glycol groups, preferably 9 to 50 polyalkylene glycol groups is preferred because it functions as a crosslinking agent and also as an antistatic agent.

The ratio of rubber trunk polymer and branch polymer is 5 to 80% by weight of the former.
, preferably 8 to 70% by weight, the latter 20 to 95% by weight
, preferably in the range of 30 to 92% by weight.

When the amount of the rubber backbone polymer is less than 5% by weight, it becomes difficult to impart antistatic properties, and when it is more than 80% by weight, the graft copolymer loses its rigidity and deteriorates moldability.

As the vinyl monomer or vinylidene monomer used in graft polymerization, known monomers can be used.

For example, acrylic acid alkyl ester, methacrylic acid alkyl ester, acrylic acid, methacrylic acid, acrylamide, methacrylamide, vinyl acetate, unsaturated nitrile, aromatic vinyl, conjugated diene, alkyl vinyl ether, alkyl vinyl ketone, 2-hydroxyethyl (meth) One or more monomers can be used, such as acrylic esters, (alkoxy)polyethylene glycol (meth)acrylic esters, diaseptone acrylamide, vinyl chloride, vinylidene chloride, itaconic acid, itaconic acid alkyl esters, isobutyne, etc. .

The antistatic resin composition of the present invention is a graft copolymer 1 consisting of the above-mentioned rubber trunk polymer containing polyalkylene oxide groups.
An excellent antistatic resin composition can also be obtained by mixing 0 to 99 parts by weight of the graft copolymer with 90 to 1 part by weight of another thermoplastic resin having good compatibility with the graft copolymer.

However, the rubber backbone polymer must be present in an amount of 5 to 80% by weight, preferably 8 to 60% by weight, based on the total amount of the graft copolymer and thermoplastic.

When the rubber backbone polymer content is 5% by weight or less, it becomes difficult to impart antistatic properties, and when it is 80% by weight or more, heat resistance and moldability deteriorate.

Examples of the thermoplastic resin of the present invention include polyethylene,
Polypropylene, polyvinyl chloride, polyvinylidene chloride, polyvinylidene fluoride, aromatic vinyl polymer, nitrile resin, polymethyl methacrylate and its copolymer,
Acrylonitrile styrene-butadiene resin, acrylonitrile-styrene resin, polycarbonate, polyamide resin, polyester resin, and fluorine resin are used, but of course, other thermoplastic resins may be used as long as they are compatible with the graft copolymer. It goes without saying that it will be used.

The graft polymer of the present invention can be produced by ordinary graft polymerization methods such as emulsion polymerization, suspension polymerization, and bulk polymerization in the presence of a radical-generating initiator. Emulsion polymerization is the most preferred method from the viewpoint of controlling properties.

In addition, when polymerizing a branched polymer, the entire amount of monomers may be added at once, or if the polymerization exotherm is large or a combination of monomers with different monomer reactivity ratios is used, The desired graft copolymer can be produced by divided addition polymerization or continuous addition polymerization according to known methods.

Although the product of the present invention can easily be made transparent by controlling the refractive index of the graft copolymer and the thermoplastic resin, it is not necessarily limited to a transparent product.

The resin composition having excellent antistatic properties of the present invention can be processed by ordinary processing methods such as injection molding, extrusion molding, compression molding, or vacuum molding.

Therefore, plastic molded products, sheets, films, tubes,
Fibers etc. can be manufactured.

Specific fields of application include, for example, electrical appliances (such as cassette tape recorder cases, TV cathode ray tube front covers, record player covers, vacuum cleaner dust collectors, instrument covers, IC device storage containers, etc.), packaging supplies (
(e.g. doll cases, cans, bottles, packaging films, etc.), acoustic materials (e.g. audio discs, video discs,
Tape for tape recorders, etc.), building materials (e.g. wall materials, flooring materials, panels, window materials, etc.), lighting equipment (e.g. light covers, displays, etc.), and other applications that use plastics and require antistatic properties. Are suitable.

The present invention will be explained below by way of examples.

Parts and % in the examples represent parts by weight and % by weight, respectively.

Regarding the measurement conditions of the sample, the humidity was adjusted as described in Example 1, and the measurement was performed one week after molding and one week after washing with water, but the product of the present invention has sufficient antistatic properties even immediately after molding or washing with water. It has a sexual nature.

Therefore, the antistatic property of the product of the present invention is not caused by the component acting as an antistatic agent bleeding onto the surface over time after moisture absorption after molding or after washing with water.

In addition, although the samples in the examples were made using a molding method in which the powder was heated and pressed, it could also be molded by kneading it with heated rolls and then pressing it, or molding it using an injection molding machine or an extrusion molding machine. show almost the same value.

Examples 1 to 4 An aqueous solution in a 10J stainless steel autoclave with a stirring blade was adjusted to pH 9.5 with an aqueous sodium hydroxide solution.
The temperature was adjusted to 10 to 10, and the mixture was sufficiently purged with nitrogen and stirred at 60°C for 10 hours.

Rubber latex with an average particle size of 0.08 μm was obtained with a yield of 99%.

(b) Add 270 parts of the above rubber latex (60 parts as a rubber backbone polymer), purify with nitrogen, stir at 50°C for 10 hours, take out the Kraft copolymerized latex, precipitate with 5% aqueous hydrochloric acid solution, and add caustic soda. The pH was adjusted to 7 with an aqueous solution, dehydrated and washed, and then dried at 50° C. for 24 hours.

A white powder was obtained with a yield of 97%. The thus obtained graft copolymer powder and bead-shaped polymethyl methacrylate resin (manufactured by Sumitomo Chemical Co., Ltd., trade name Sumipex B)
-LG) in the proportions shown in Table 1 using a Henschel blender, then kneading for 3 minutes with a hot roll at 170°C.
A test piece with a thickness of 0.6 to 0.8 was made by press molding at 00°C and 200 kg/cwt for 5 minutes.
Table 1 shows the results of measuring the half-life of the electrostatic voltage using a static honest meter (manufactured by Shishido Korosha) after storage for one week under standard conditions of 50% RH and 50% RH.

The measurement conditions of the static honest meter are as follows.

Washing resistance was determined by cleaning the surface of the sample with the detergent Mama Lemon (Lion Oil K).
After thoroughly washing with an aqueous solution (manufactured by K), thoroughly washing with distilled water, and then storing the sample at 50% RH for 1 week at 123°C and adjusting the humidity, the half-life of IT pressure was determined using a static honest meter. It was measured.

The proportion of the rubber backbone polymer in the entire composition is as shown in Example 1.2.3.
．． 4 were 12%, 21%, 30%, and 45%, respectively.

Example 5 A 101 stainless steel autoclave equipped with a stirring blade was charged, the atmosphere was sufficiently purged with nitrogen, and the mixture was stirred at 50'C for 20 hours.

Rubber latex with an average particle size of 0.08 μm was obtained with a yield of 99%.

(b) Add 320 parts of the above latex (80 parts as a rubber backbone polymer), replace with nitrogen, stir at 50°C for 20 hours, and graft copolymerize to obtain a graft copolymer latex with a yield of 97%. Ta.

(]31) was placed in a stainless steel autoclave equipped with a stirring blade, the atmosphere was sufficiently purged with nitrogen, and the mixture was stirred at 50°C for 15 hours.

A thermoplastic resin latex was obtained with a yield of 99%.

25 parts by weight of the graft copolymer latex polymerized in (4) and 75 parts by weight of the thermoplastic resin latex polymerized in (B) were thoroughly mixed in a latex state, and then a 5% aqueous aluminum sulfate solution was added to precipitate the pyrroline. The pH was adjusted to 7 with a saturated aqueous sodium acid solution, and after dehydration and washing, the mixture was dried at 50° C. for 24 hours.

A white powder was obtained with a yield of 98%.

A test piece was made from this powder in almost the same manner as in Example 1,
The half-life of the charged voltage was measured using a static honest meter.

The results are as follows. *Examples 6 to 10 Samples were mixed with Sumipex B-LG in the same manner as in Example 3 except that the monomer composition of the graft copolymer used in Example 3 was changed as shown in Table 2. Table 2 shows the results measured using a static honest meter.

The symbols used in the table below are also the same as in Table 2.

Example 11 An aqueous solution consisting of the above was adjusted to pH 7 with an aqueous sodium hydroxide solution and charged into a 101 stainless steel oak crepe with a stirring blade, the atmosphere was sufficiently purged with nitrogen, and the mixture was stirred at 40°C for 20 hours.

Rubber latex with an average particle size of 0.08μ was obtained with a yield of 99%.

(b) Add 200 parts of the above rubber latex (50 parts as a rubber backbone polymer), purify with nitrogen, stir at 50°C for 20 hours, take out the graft copolymerized latex, precipitate with an aqueous aluminum sulfate solution, and pyrophosphoric acid The pH was adjusted to 7 with an aqueous sodium solution, and after dehydration and washing, it was dried at 55° C. for 24 hours.

A white powder was obtained with a yield of 97%.

40 parts by weight of the thus obtained graft copolymer and 60 parts by weight of polymethyl methacrylate resin (manufactured by Asahi Dow Co., Ltd., trade name Delpera 6ON) were kneaded for 3 minutes with a heated roll at 170°C, and then kneaded at 200°C and 200 kg/kg. A test piece with a thickness of 0.6 to 0.8 mm was made by press molding for 5 minutes with crA, and after storing this test piece for one week under standard conditions of 23°C and 50% RH, it was placed on a static honest meter (Muroto). The antistatic property was determined by measuring the half-life of the charging voltage using a 300-millimeter (manufactured by Shokai).

The results are shown in Table 3. Examples 12, 3 A graft copolymer was produced in the same manner as in Example 11, except that methyl acrylate in Example 1 was replaced with styrene, 50 parts of methyl methacrylate was replaced with 37.5 parts of styrene, and 12.5 parts of acrylonitrile. .

40 parts of this graft copolymer, 60 parts each of acrylonitrile-butadiene-styrene resin (manufactured by Toyo Rayon Co., Ltd., trade name TOYOLAC 900) and acrylonitrile-styrene resin (manufactured by Shio Dow Co., Ltd., trade name Tyril 780) were heated at 170°C.
After kneading with a hot roll for 3 minutes, a sample was prepared in the same manner as in Example 1, and the results of measurement with a static honest meter are shown in Table 3.

Examples 14 to 17 * * 20 parts of the graft copolymer shown in Table 4 and 80 parts of the thermoplastic plastic shown in Table 4 were heated at 220 to 270°C.
After kneading for 3 minutes in a thermal kneader, 220-280℃,
Samples were prepared by pressing at 200 kg/crA for 3 minutes and measured using a static honest meter, and the results are shown in Table 4.

Comparative Examples 1-4 Example 14-4 except that no graft copolymer was added
A sample was prepared in exactly the same manner as in No. 17 and measured using a static honest meter, and the results are shown in Table 4.

Example 18 20 parts by weight of the graft copolymer used in Example 1 and a polyvinyl chloride compound (100 parts of polyvinyl chloride with an average degree of polymerization of 700, 2 parts of dibutyltin mercaptide, 2.3 parts of dibutyltin malate polymer) A total of 80 parts by weight of 0.7 parts of stearyl alcohol and 0.2 parts of montanic acid phthylene gelicol ester) were mixed and kneaded for 3 minutes with a hot roll at 160°C, and a test piece was prepared in the same manner as in Example 1. The half-life of the built-up electrostatic voltage was measured.

The results are shown below. Example 19 50 parts of the graft copolymer used in Example 1 and 50 parts of beaded styrene-acrylonitrile resin (Daicel Chemical, Sepian N) were kneaded for 3 minutes with a heated roll at 170°C, and then mixed in the same manner as in Example 1. A test piece was prepared using a standard method, and the half-life of the charged voltage was measured using a static honest meter.

The results are as follows.

The same sample was also molded using an injection molding machine to a size of 200 x 50 x 3 m.
A plate of m was molded.

The resin temperature during molding was 240°C, and the mold temperature was 60°C.

The antistatic properties of this plate are as follows.

Example 20 35 parts of the graft copolymer latex used in Example 5 and 65 parts of the thermoplastic resin latex were latex blended and subjected to the same post-treatment as in Example 5 to produce a white powder.

Using this powder, 200 x 50 x 3 m was made by injection molding.
A plate of m was molded.

At this time, the resin temperature was 240°C and the mold temperature was 60°C.

The antistatic properties of this plate were measured in the same manner as in Example 5, and the results are shown below.

Comparative Example 5 A test piece was prepared in the same manner as in Example 5, except that 16 parts of methoxypolyethylene glycol methacrylate was replaced with 16 parts of butyl acrylate, and the antistatic property was measured.

The results are as follows. Comparative Example 6 A test piece was prepared in the same manner as in Example 5 except that 16 parts of methoxypolyethylene glycol methacrylate was replaced with 16 parts of methoxydiethylene glycol methacrylate, and the antistatic properties were measured. The results are as follows.

Claims (1)

[Scope of Claims] 1(A) 50 to 90% by weight of one or more monomers selected from conjugated dienes and acrylic esters, the following formula (I), (
Consisting of 10 to 50% by weight of a monomer having an alkylene oxide group selected from the compounds represented by II) and O to 49% by weight of one or more copolymerizable vinyl monomers or vinylidene monomers, if necessary. Rubber trunk polymer 5
10 to 99 parts by weight of a graft copolymer obtained by graft copolymerizing ~80% by weight with 20 to 95% by weight of one or more vinyl monomers or vinylidene monomers, and (B) the above graft copolymer. and 90 to 1 part by weight of a thermoplastic resin that is compatible with (with 4))
(total sum of 100 parts by weight), and an antistatic resin composition in which the proportion of the rubber backbone polymer is 5 to 80% by weight. [R1, R2, R3 are hydrogen or an alkyl group having 1 to 4 carbon atoms, X is hydrogen or an alkyl group having 1 to 9 carbon atoms, m and n are 4≦m + n≦5000