JPS6399263A - Processing assistant for thermoplastic resin and thermoplastic resin composition produced by using same - Google Patents

Abstract

PURPOSE:To provide the titled processing assistant composed of a polymer of methyl methacrylate and other vinyl monomer and produced by the emulsion polymerization in the presence of a specific emulsifier, and effective in preventing the problems such as thermal discoloration in molding by compounding to a thermoplastic resin. CONSTITUTION:The objective processing assistant is composed of a copolymer having a reduced viscosity of 2-0.1, preferably 1.5-0.1 (at 25 deg.C) and produced by the emulsion polymerization of (A) 35-99.9wt% methyl methacrylate unit and (B) 0.1-65wt% other vinyl monomer unit copolymerizable with the monomer A (e.g. ethyl acrylate, styrene, etc.) in the presence of (C) an emulsifier of formula (R is 10-24C, preferably 12-18C alkyl or alkenyl; M is Na or K) and a polymerization initiator (e.g. sodium persulfate). 0.1-40pts.wt. of the processing assistant is added to 100pts.wt. of a thermoplastic resin (e.g. vinyl chloride resin, acrylonitrile-styrene resin, methyl methacrylate-styrene resin, etc.).

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a processing aid for thermoplastic resins, and more specifically, it improves the processability of thermoplastic resins when blended with them, and also improves the processability of said resins. A thermoplastic resin that is less likely to be thermally colored even when it is heat molded, and furthermore, even when a molded article of the resin is used in contact with water, there is less leakage of eluates that would deteriorate water quality. and a thermoplastic resin composition using the same.

[Prior Art] Thermoplastic resins, particularly vinyl chloride resins, have excellent physical and chemical properties and are therefore widely used in various fields. However, since the temperature at which polyvinyl chloride resin can be heated and the thermal decomposition temperature are close to each other, the temperature range in which it can be molded is extremely narrow, and its gelation rate is slow. It has the problem of being inferior.

In order to solve these problems, a method has been used in which plasticizers are added to vinyl chloride resins, but although this method alleviates the above problems to some extent, the plasticizers added during hot molding A new problem arises in that it is difficult to sufficiently achieve the original purpose because the agent volatilizes, and the mechanical properties of the resulting molded product deteriorate.

In addition, it accelerates the gelation rate during molding of vinyl chloride resin, enables deep drawing, and maintains the same gloss on the surface of the molded product even during long molding processes. , for the purpose of improving the so-called processability, such as smoothing the surface of the obtained molded body,
A method has been proposed in which a copolymer containing methyl methacrylate as a main component is blended as a processing aid (for example, Japanese Patent Publication No. 49-17075, Japanese Patent Publication No. 50-37697,
(See Japanese Publications No. 52-1746, No. 51-33821, and No. 53-2898).

Vinyl chloride resin compositions containing processing aids made of such specific copolymers have a high gelation rate during molding and have increased tensile elongation at high temperatures, making deep drawing possible. Not only this, but also vacuum forming, profile extrusion, etc. can be applied, so the secondary processability in the field of hard vinyl chloride resins can be greatly improved.

In addition, the vinyl chloride resin composition disclosed in the above-mentioned Japanese Patent Publication No. 52-1746 has less occurrence of fish eyes in its molded products, so it is used not only in the field of hard resins.
This makes it possible to apply it to the soft resin field.

However, copolymers, which are processing aids blended into vinyl chloride resins, are generally manufactured by emulsion polymerization for ease of production, so it is possible for emulsifiers to remain in the copolymer. There is a problem that this residual emulsifier has a negative effect on the thermoplastic resin.
For example, if the heat during molding process causes coloring on the surface of the molded product due to emulsifier residue, or if such a vinyl chloride resin composition is molded into a vibrator or the like and used in contact with water. In addition, the remaining emulsifier may be eluted into water, which may cause deterioration of water quality. Furthermore, when used as a constituent material for food containers and the like, residual emulsifier liquid may dissolve into the food, impairing the taste and aroma of the food.

[Problems to be Solved by the Invention] As mentioned above, thermoplastic resins such as vinyl chloride resins that have been blended with processing aids made of specific copolymers have There are problems such as thermal coloring during molding and water contamination and food contamination due to residual emulsifier.

Therefore, the present invention solves such problems, and even when the emulsifier used during production remains in the processing aid blended into thermoplastic resins such as vinyl chloride resins, the above-mentioned problems can be solved. The object of the present invention is to provide a processing aid for thermoplastic resins that does not cause spots, and a thermoplastic resin composition using the same.

[Means for Solving the Problems] As a result of studies conducted by the present inventors to achieve the above object, it was found that the emulsifier used during the production of the thermoplastic resin remains in the processing aid blended into the thermoplastic resin. The present invention has been completed by discovering an emulsifier that does not have any adverse effect on the thermoplastic resin even when the emulsifier is used.

That is, the processing aid for thermoplastic resins of the present invention contains 35 to 99.9% by weight of units based on methyl methacrylate and 0.9% by weight of units based on other vinyl monomers copolymerizable with the methyl methacrylate. 1 to 65% by weight of a thermoplastic resin processing aid, wherein the polymer has the following formula (1); or an alkenyl group; M represents sodium or potassium) by applying an emulsion polymerization method in the presence of an emulsifier, and furthermore, the thermoplastic resin composition of the present invention is based on 100 parts by weight of thermoplastic resin,
Based on methyl methacrylate (units 35-99.9% by weight)
and 0.1 to 65% by weight of units based on other vinyl monomers copolymerizable with the methyl methacrylate.

The polymer is subjected to an emulsion polymerization method in the presence of an emulsifier represented by the following formula (1); It is characterized in that it contains 0.1 to 40 parts by weight of a processing aid for thermoplastic resin obtained by applying.

The processing aid for thermoplastic resins of the present invention is produced by combining a predetermined amount of methyl methacrylate and other vinyl monomers copolymerizable with the methyl methacrylate, a specific emulsifier, a polymerization initiator, and other catalysts as necessary. It can be obtained by emulsion polymerization in the presence of.

Examples of other vinyl monomers copolymerizable with methyl methacrylate used in the present invention include one or more selected from acrylic acid alkyl esters, methacrylic acid alkyl esters, aromatic vinyl compounds, vinyl cyanide compounds, etc. can be used.

Among such vinyl #1 mer, the acrylic acid alkyl ester preferably has an alkyl group having 2 to 10 carbon atoms.For example, ethyl acrylate, propyl acrylate, n-butyl acrylate, acrylic acid Examples include isobutyl, hexyl acrylate, octyl acrylate, and 2-ethylhexyl acrylate.

As the methacrylic acid alkyl ester, carbon la2~
Preferred examples include ethyl methacrylate, propyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, and tert-butyl methacrylate.

Examples of the aromatic vinyl compound include styrene, α-substituted styrene, nuclear-substituted styrene, and derivatives thereof, such as α-methylstyrene, clofrestyrene, and vinyltoluene.

Furthermore, examples of vinyl cyanide compounds include acrylonitrile and methacrylonitrile.

Such vinyl intermediates can be appropriately selected and used depending on the intended use of the resin modifier.

The blending of methyl methacrylate and a vinyl-based compound capable of copolymerizing with it is such that in the copolymer obtained by performing a polymerization reaction, <I'lx position is 35 to 99 based on methyl methacrylate. .9 type needles, and the unit based on other vinyl intermediates is 0.1 to 65 nail amount%.

In this case, methyl methacrylate monomer is 35 FJt%
If it is less than that, the compatibility with vinyl chloride resin will deteriorate,
The desired processability imparting effect cannot be obtained, and the transparency of the molded product deteriorates. Furthermore, if the amount of copolymerizable vinyl/lj soft units is less than 0.1%, although there is a suitable goo effect with adding properties, fish eyes (ungelled substances) may occur in the molded product. Cheap.

The emulsifier used in the present invention is a compound represented by the above formula (I). In formula (I), the group R has 10 to 24 carbon atoms.
is an alkyl group or alkenyl group, especially one having 1 carbon number.
2 to 18 alkyl or alkenyl groups are preferred, and M is sodium or potassium.

When the compound represented by formula (I) is used as an emulsifier, it increases the number of polymer particles produced during polymerization, increases the polymerization rate, and , the polymerization conversion rate can be increased, the generation of aggregates of the particles is extremely small, and the mechanical stability of the latex after polymerization is also excellent.

The amount of the compound represented by formula (I) is based on 100 parts by weight of the total amount of intermediate components.

The amount is 0.1 to 10 parts by weight, preferably 0.5 to 5 parts by weight. If the amount used is less than 0.1 part by weight, the stability of the polymerization reaction will decrease, and if it exceeds 10 parts by weight, the amount of emulsifier remaining in the resulting copolymer will be too large. Decreases the physical properties of resin moldings when used as a processing aid.

As the polymerization initiator used in the present invention, an inorganic initiator such as a normal persulfate, an organic peroxide, an azo compound, etc. may be used alone, or the above compound and a sulfite, hydrogen sulfite, or 1,000 sulfate may be used. , the metal amount n, and sodium formaldehyde sulfoxylate. Preferred persulfates as polymerization initiators include sodium persulfate, potassium persulfate, ammonium persulfate, etc., and examples of organic peroxides include tert.
-butyl hydroperoxide, cumene hydroperoxide, benzoyl peroxide, lauroyl peroxide and the like.

The polymerization method can be carried out in the same manner as the usual emulsion type method while heating to a temperature higher than the decomposition temperature of the 1st polymer initiator used, and polymerization can be carried out in the 1st or 2nd stage. In addition, in this polymerization reaction, the molecular weight and molecular weight distribution of the resulting copolymer have a large effect on its properties as a processing aid, so the molecular weight etc. can be adjusted by appropriately setting the polymerization conditions or using a chain transfer agent. It is preferable to adjust.

That is, the quinary viscosity of the obtained copolymer ηsp/c (measured at 25°C using an Ostwald viscometer for a solution of O.Ig copolymer dissolved in 100.7 chloroform) value) is 2 to 0.1,
It is desirable to carry out the polymerization reaction so that the ratio is preferably 1.5 to 0.1.

To recover the copolymer, after the polymerization reaction is completed, the copolymer latex produced is coagulated by salting out or acid precipitation.

After the copolymer is precipitated, it can be separated and washed to recover the powder, or it can be recovered in the form of a powder by spray drying or freeze drying.

The processing aid of the present invention thus obtained can be applied as a processing aid for thermoplastic resins, and examples of such thermoplastic resins include vinyl chloride resins, polycarbonate resins, polyethylene resins, Examples include polyester resins, acrylonitrile-styrene copolymer resins, methyl methacrylate-styrene copolymer resins, and ABS resins. Among these resins, as the vinyl chloride resin, in addition to polyvinyl chloride, a copolymer containing 70% by weight or more of units based on vinyl chloride can be used. When using such a copolymer as a vinyl chloride resin, examples of monomers copolymerizable with vinyl chloride include ethylene, propylene, vinyl bromide,
Vinylidene chloride, vinyl acetate, acrylic ester, methacrylic ester, etc. can be used.

When the processing aid of the present invention is blended with a thermoplastic resin, it is preferably mixed in a powdered state using, for example, a ribbon blender or a Henschel mixer. In addition, in the case of molding, the mixture is further kneaded using, for example, a mixing roll or a Banbury mixer, and then is carried out using an extruder, an injection molding machine, or the like.

The blending amount of the processing aid is 0.1 to 40 parts by weight, preferably 0.1 to 30 parts by weight, per 100 parts by weight of the thermoplastic resin.
Parts by weight. If the blending amount is less than 0.1 parts by weight, the improvement in the processability of the resin will be insufficient, and if it exceeds 40 parts by weight, the mechanical properties inherent in the resin will be impaired. .

In addition, when blending the processing aid of the present invention with a thermoplastic resin, known stabilizers, plasticizers, lubricants, colorants, impact resistance modifiers, etc. may also be blended as necessary. You can also do it.

[Example] The present invention will be explained in more detail with reference to Examples below. In addition, in the following, "parts" and "%" each refer to "parts by weight".
and “% by weight”.

Example 1 Ion-exchanged water 20 in which dissolved oxygen was replaced with nitrogen in a reaction vessel
0 parts, and the group R has 16.17 and 18 carbon atoms.
is an alkyl group and M is potassium (1
) and 0.3 parts of potassium persulfate were charged in the reaction vessel.Next, the temperature inside the reaction vessel was raised to 65°C with stirring, and then 85 parts of methyl methacrylate and acrylic acid were added. 10 parts of methyl, 5 parts of butyl acrylate, and 0.05 parts of tert-dodecyl mercaptan
of the mixture was added dropwise over a period of 1 hour. After the dropwise addition was completed, the inside of the container was maintained at the same temperature for another 2 hours to complete one reaction, and a copolymer latex was obtained with a polymerization conversion rate of 99.
5%, almost no aggregates were generated in the latex, and the mechanical stability of the latex was extremely good.

While stirring the resulting copolymer latex.

The copolymer produced by adding it to a 1% aqueous sulfuric acid solution was precipitated.Next, the precipitated copolymer was separated, washed, dehydrated, and dried to obtain a powdered processing aid. Ta.

Example 2 Ion exchange water 2 in which dissolved oxygen was replaced with nitrogen was placed in a reaction vessel.
00 parts, and the group R has 12.13 and 1 carbon atoms.
4 is an alkyl group, and M is potassium, three types of formulas (
1.2 parts of an emulsifier consisting of a mixture of the compounds shown in 1) and 0.5 parts of potassium persulfate were charged.Next, the inside of the reaction vessel was heated to 70°C for 4 hours while stirring, and then 35 parts of methyl methacrylate was added. , 5 parts of acrylic ethyl and n −
A mixture consisting of 0.02 parts of octyl mercaptan was added dropwise over 1 hour while stirring.After the dropwise addition was completed, the first stage polymerization was carried out by holding at the same temperature for 2 hours.Next,
While stirring inside the reaction vessel, add 30 parts of styrene, 25 parts of ac-1-noryl ester, and 0.3 n-octyl mercaptan.
After the completion of the dropwise addition, the mixture was kept at the same temperature for 1 hour to carry out the second stage polymerization.

While stirring the inside of the reaction vessel, 5 parts of methyl methacrylate was added dropwise over 1 hour, and the temperature was further maintained for 2 hours to carry out the third stage polymerization to obtain a copolymer latex. The rate was 99.9%, there were almost no aggregates in the latex, and the mechanical stability of the latex was extremely good.

The obtained copolymer latex was treated in the same manner as in Example 1 to obtain a powdery processing aid.

Comparative Example 1 A processing aid was obtained in the same manner as in Example 1, except that one part of semi-hardened beef tallow fatty acid soap was used instead of the emulsifier used in Example 1.

Examples 3 to 4 and Comparative Examples 2 to 3 100 parts of vinyl chloride resin with an average degree of polymerization of 700, 1.8 parts of dibutyltin malate, 1 part of butyl stearate, and a lubricant. A common formulation of 0.7 parts.

After blending 3 parts each of the processing aids obtained in Examples 1 and 2 and Comparative Example 1, the mixture was mixed until the temperature reached 120°C using a Henschel mixer to obtain three types of vinyl chloride resin compositions. Ta.

The following tests were conducted using the three types of resin compositions obtained. As a comparative test example, a composition having the same composition as in -1- except that no processing aid was added was used. The results are shown in Table 1.

1) Using a Brabender plasticorder, kneading temperature 185°C, rotation speed 3 Orpm, filling "J60g"
The time (minutes) until the kneading resistance reached its maximum value, that is, the gelation time (minutes), was measured under the conditions of preheating for 5 minutes. The shorter this time, the faster the gelation and the easier the processing.

2) Single screw extruder with a screw diameter of 40 mm equipped with a T-gui (extrusion tank temperature C, = 140''C1C2 = 160
℃, C3=180℃ and C4=190℃, die temperature 1
95°C) to prepare a sheet with a thickness of 0.2 mm,
The appearance of the film was visually judged. The judgment criteria are as follows.

A: Good gloss and smooth surface.

B: Lack of gloss and rough surface.

3) The 0 criterion for visually judging the number of ungelled substances on the sheet surface obtained in 2) is as follows.

A: Not at all.

B: Slightly high.

4) The sheet obtained in 2) was cut into four pieces of 3 cm in size and fixed in an aluminum acid frame.
It was placed in a gear oven whose temperature was adjusted to 185°C, and the state of thermal coloring was visually judged. The judgment criteria are as follows.

There is almost no ARM band color.

B: Some color bands were observed.

As is clear from Table 1, the compositions containing the processing aids obtained in Examples 1 and 2 had excellent processability and heat-resistant coloring properties.

Example 5 Ion-exchanged water 20 in which dissolved ugliness was replaced with nitrogen in a reaction vessel
0 parts, and further added 55 parts of methyl methacrylate, 5 parts of ethyl acrylate, and 0.02 parts of n-octyl mercaptan.
1.2 parts of an emulsifier consisting of a mixture of three compounds represented by formula (I) in which the group R is an alkyl group having 12, 13 or 14 carbon atoms and M is potassium, and 0.2 parts of potassium persulfate. I prepared the parts all at once. Next, after purging the inside of the container with nitrogen, the temperature was raised to 65° C., and the first stage polymerization was carried out by heating and stirring at the same temperature for 2 hours. Thereafter, a mixture consisting of 34 parts of methyl methacrylate and 6 parts of butyl acrylate was added dropwise into the reaction container over 1 hour while maintaining the inside of the container at 65°C and stirring. The temperature was maintained for 2 hours, and a second stage of polymerization was performed to obtain a copolymer latex. There were almost no aggregates in the latex, and the mechanical stability of the latex was also very good.

The obtained copolymer latex was treated in the same manner as in Example 1 to obtain a powdery processing aid.

Comparative Example 4 A processing aid was obtained in the same manner as in Example 5, except that 1 part of sodium dialkyl sulfosuccinate was used instead of the emulsifier used in Example 5.

Example 6 and Comparative Example 5 20 g of each of the processing aids obtained in Example 5 and Comparative Example 4,
After adding it to 100 - ion exchange water, it was heated at 50℃ for 30
After holding for a minute, the temperature was further held at 80°C for 3 hours.

Thereafter, the solution was suction-filtered using No. 5C Shichito paper.The resulting Shitto liquid was then evaporated to dryness, and the amount of eluate in water was determined from the weight of the residue. In addition, the properties of the furnace liquid were observed with the naked eye. The results are shown in Table 2.

As is clear from Table 2, the processing aid obtained in Example 5 had very little eluate with water.

Example 7 and Comparative Examples 6 to 7 ■ Vinyl, 100 parts of vinyl chloride resin with an average degree of polymerization of 700, methyl methacrylate-butadiene-styrene copolymer Metabrene@C-201 (trade name; manufactured by Mitsubishi Rayon ■) ), 2 parts of octyltin mercaptide stabilizer, 1 part of epoxy stabilizer, 0.8 part of stearic butyl, and 0.3 part of polyglycol ester of fatty acid, Example 5
After blending 1.5 parts each of the processing aids obtained in Comparative Example 4, the mixture was heated to 120°C and mixed using a Henschel mixer to obtain two types of vinyl chloride resin compositions. Ta.

Using each of the obtained resin compositions, bottles were molded using a blow molding machine with a screw diameter of 40 mm, and the following evaluations were performed. As a comparative example, a composition having the same composition as above except that no processing aid was added was used. The results are shown in Table 3.

1) Parison drawdown A during molding; die swell is large and there is no drawdown.

B: Dice swell has a small drawdown.

2) Visual judgment of bottle appearance A: Good gloss and no rough skin.

B: Poor luster and noticeable rough skin.

3) Visual observation of the state of ungelled matter on the bottle wall A: Almost no ungelled material was observed.

B: A small amount of ungelled material was observed.

4) Amount of eluate relative to water After washing the obtained bottle with a commercially available odorless neutral detergent, the inside of the bottle was filled with ion-exchanged water and kept at 50°C for 10 hours. After that, I gave the liquid contents to 7 people with No. 50 paper.

Next, the obtained liquid was evaporated to dryness, and the resulting residue was dissolved in carbon tetrachloride, and IRJlll determination was performed.

5) Taste test I: After washing the obtained bottle with a commercially available odorless neutral detergent, the inside of the bottle was filled with ion-exchanged water and then held at 50°C for 3 hours.The taste of the ion-exchanged water was examined. The 0 judgment was made by a panel of 45 people who are very sensitive to taste. Display 1
If 3 or more out of 5 panel members judged that there was no change in taste, it would be marked ○, and if it was judged that there was a change in taste, it would be marked ×.

Examples 8 to 12 and Comparative Examples 8 to 12 100 parts of each of the following thermoplastic resins were mixed with and without 3 parts of the processing aid obtained in Example 1 using a Henschel mixer. The resulting mixture was pelletized using an extruder with a screw diameter of 40 mm, and
Drying was performed at 80° C. for 1 hour or more. Next, using a blow molding machine with a screw diameter of 40 mm, bottle molding was performed for each resin at different temperatures as shown below, and each test listed in Table 4 was conducted according to Examples 3 and 7.

(1) ABS resin (Diapet I'ABSa3
001; Product name, Mitsubishi Rayon auxiliary) Molding temperature: C =
180°C, C2 = 200”c, c3 = zooo°C, head = 200°C, die = 200°C (2) Styrene resin (styrene NF-20; trade name,
Idemitsu petrochemical auxiliary equipment) Molding temperature: C1 = 160°C, C2 = 180°C, C, = 2
00°C, head -200°C.

Dice = 210℃ (3) Polycarbonate resin (Tubarex 7022,
Product name: Mitsubishi Kasei Kogyo) Molding temperature: C1 = 230℃
, C2=260℃, C3=270℃, head=270℃
, die = 280°C (4) Polyethylene resin (Hi-Kamitsufu 000F; trade name, manufactured by Mitsui Petrochemical Industries, Ltd.) Molding temperature: C1 = 150°C, C2 = 165°C, C, =
175°C, head = 175°C, die = 175°C (5) Polyester resin (Dyanite 0A-200;
Product name: Mitsubishi Rayon Auxiliary) Molding temperature: C1 = 280℃
, C2=280℃, C3=280℃, head=260℃
, die = 260° C. As is clear from Table 4, the same excellent processability was observed in all the thermoplastic resins blended with the processing aid of Example 1, even when the types were different.

[Effects of the Invention] As explained above, the processing aid of the present invention can improve the molding processability of various thermoplastic resins by blending it with the resin, and can also improve the molding processability of the resin. Even when heated, the surface of the molded product will not be colored unfavorably.Furthermore, even when the molded product obtained from the resin is used in contact with water, no substances will be eluted into the water from the molded product. Since there is almost no water pollution, there are no problems with water contamination, such as deteriorating the taste of water or producing bad odors.

Claims (1)

[Claims] (1) Units based on methyl methacrylate 35 to 99.9
% by weight and 0.1 to 65% by weight of units based on other vinyl monomers copolymerizable with the methyl methacrylate, the processing aid for thermoplastic resins comprising: , the said polymer has the following formula (I); ▲There are mathematical formulas, chemical formulas, tables, etc.▼(I) (In the formula, R represents an alkyl group or alkenyl group having 10 to 24 carbon atoms; M represents sodium or potassium. A processing aid for thermoplastic resins, characterized in that it is obtained by applying an emulsion polymerization method in the presence of an emulsifier represented by: (2) Based on 100 parts by weight of the thermoplastic resin, 35 to 99.9% by weight of units based on methyl methacrylate and 0.1 units based on other vinyl monomers copolymerizable with the methyl methacrylate. A processing aid for thermoplastic resins consisting of a polymer consisting of ~65% by weight, where the polymer has the following formula (I); ▲There are mathematical formulas, chemical formulas, tables, etc.▼(I) , R represents an alkyl group or alkenyl group having 10 to 24 carbon atoms; M represents sodium or potassium) A processing aid for thermoplastic resins obtained by applying an emulsion polymerization method in the presence of an emulsifier represented by 0 .1 to 40 parts by weight of a thermoplastic resin composition. (3) The thermoplastic resin composition according to claim 2, wherein the thermoplastic resin is a vinyl chloride resin. (4) The thermoplastic resin composition according to claim 2, wherein the thermoplastic resin is an acrylonitrile-styrene resin or a methyl methacrylate-styrene resin. (5) The thermoplastic resin composition according to claim 2, wherein the thermoplastic resin is an ABS resin. (6) The thermoplastic resin composition according to claim 2, wherein the thermoplastic resin is a polycarbonate resin. (7) The thermoplastic resin composition according to claim 2, wherein the thermoplastic resin is a polyethylene resin. (8) The thermoplastic resin composition according to claim 2, wherein the thermoplastic resin is a polyester resin.