KR100375858B1 - Method for producing flat vinyl chloride resin having excellent processability - Google Patents

Abstract

PURPOSE: Provided is a method for producing a crosslinking, flat copolymer formed by copolymerizing a monomer capable of crosslinking a monomer mixture based on vinyl chloride monomer, which has excellent mechanical property, heat resistance, and chemical resistance. CONSTITUTION: In the method, 0.001-3 parts(with respect to 100 parts of vinyl chloride monomer) of at least two kinds of crosslinking agents including 0.005-2 parts of silane-based crosslinking agent of formula 1, 0.005-2 parts of primary dispersing agent, 0.005-1 parts of secondary dispersing agent selected from the group consisting of sorbitan tristearate, sorbitan trioleate, sorbitan monooleate, sorbitan monopalmitate, glyceromonooleate, glycerol monostearate, triglycerol monooleate, and PVA(polyvinyl alcohol) having hydration degree of 50% or less, and 0.001-0.5 parts of initiator; and polymerization temperature of 30-75 deg.C is used. Formula 1: CH2=C(R1)-Xm-R2n-Si(R3p)Yq(wherein R1, R2 and R3 are alkyl group, X is -CO2-, m is 0 or 1, n and p are 0 or integer; Y is -OCH3-, -OCH2CH3, -OCH2CH2CH3, -OCH(CH3)2, -OCH2CH2OCH3 or -OCOCH3, q is 1, 2 or 3).

Description

Matte vinyl chloride resin manufacturing method with excellent processability

The present invention relates to a method for producing a crosslinked matte copolymer obtained by copolymerizing a monomer having a crosslinking ability with respect to a monomer mixture mainly containing vinyl chloride monomer. Polymerized matte vinyl chloride resin has excellent mechanical properties, heat resistance and chemical resistance and includes a considerable amount of gel. Matte resin is molded and processed by mixing small amount with general resin, and it can be effectively used in soft products because of crosslinking property of resin itself, but matte resin can be used for hard processing by lowering degree of polymerization and degree of crosslinking. Depending on the degree of polymerization and the degree of crosslinking of the resin, molded articles can be manufactured using all major molding techniques such as extrusion, injection, and cadering.

A comonomer commonly used as a crosslinking agent in the production of crosslinked matte vinyl chloride resins is diallyphthalate (hereinafter DAP). After polymerizing vinyl chloride monomer by changing the amount of DAP at a constant polymerization temperature, the resin was dissolved in THF, the degree of polymerization was measured for dissolved matter, and the gel content was measured for non-hazardous THF. It can be observed that the content increases and the degree of polymerization changes significantly. As in the case of using DAP as a crosslinking agent, if the degree of polymerization of the matte resin is sensitively changed depending on the amount of crosslinking agent used, it is difficult to maintain a constant degree of polymerization of the resin in the polymerization step. On the other hand, many polyoxyalkylene compounds are known as a crosslinking agent which can adjust polymerization degree easily.

Another problem that occurs when polymerizing matte resin using DAP as a crosslinking agent is that the gloss reduction effect of the matte resin varies greatly depending on the molding conditions. Although the matting effect decreases as the molding conditions are severe, it is difficult to maintain the glossiness of the molded article at a severe level under severe processing conditions when the matte effect is greatly reduced as in a resin polymerized using DAP as a crosslinking agent.

Matte vinyl chloride resin has its own crosslinking properties, which makes processing very difficult compared to general vinyl chloride resin. Therefore, in the case of using a matte resin, the processing conditions are harsh and plasticizers are used excessively. In addition, in recent years, various attempts have been made to increase the voids of the resin in order to improve the processability of the matte resin by using a comonomer having a flexible molecular structure as a crosslinking agent or allowing the plasticizer to easily penetrate into the resin particles. As a crosslinking agent having a flexible structure, a compound having an ethylene oxide repeating unit in a molecule is typical. As a compound mainly used to increase the porosity of the resin, a surfactant having a high utility is mainly used, and a low degree of water PVA is typical.

In the present invention, a secondary dispersant was introduced to improve the processability of the crosslinked matte resin, and two or more crosslinking agents including a silane-based crosslinking agent were mixed as a crosslinking agent in order to suppress a change in glossiness of the molded article according to processing conditions.

Matte vinyl chloride resin is used for bulk polymerization, suspension polymerization, microsuspension polymerization and emulsion polymerization using a compound having two or more double bonds in its molecule as a crosslinking agent for a vinyl chloride monomer or a mixture of vinyl compounds mainly containing vinyl chloride monomer. Copolymerized crosslinked vinyl chloride resin. In the present invention, the polymerization was carried out mainly on the suspension polymerized matte resin.

Comonomers used for copolymerization with vinyl chloride monomers include acrylic acid, methacrylic acid, ethacrylic acid, α-cyanoacrylic acid, methyl acrylate, ethyl acrylate, butyl acrylate, octyl acrylate, cyanoethyl acrylate, Vinyl acetate, methyl methacrylate, ethyl methacrylate, butyl methacrylate, acrylonitrile, methacrylonitrile, methyl acrylamide, N-methylol acrylamide, X-butoxy methacrylamide, ethyl vinyl ether, Chloroethyl vinyl ether, α-methylstyrene, vinyltoluene, chlorostyrene, vinylnaphthalene, vinylidene chloride, vinyl bromide, vinylchloroacetate, vinyl acetate, vinylpyridine, methylvinyl ketone and the like are used. The amount of comonomer depends on the type of comonomer and the purpose of use of the resin.

Compounds used as crosslinking agents have two or more double bonds in the molecule, such as diallyl phthalate, diallyl terephthalate, diallyl maleate, diallyl fumarate, diallyl itaconate, diallyl adipate, diallyl ether and tri Allyl cyanurate, triallyl isocyanurate, ethylene glycol divinyl ether, n-butanediol divinyl ether, octadecane divinyl ether, vinyl acrylate, vinyl methacrylate, allyl acrylate, allyl methacrylate, ethylene Glycol diacrylate, ethylene glycol dimethacrylate, triethylene glycol dimethacrylate, diethylene glycol diacrylate, triethylene glycol diacrylate, polyethylene glycol diacrylate, polyethylene glycol bisallylcarbonate, trimethylolpropane tree Methacrylate and trimethylolpropanetriacrylate It is used. The amount of crosslinking agent is usually used in an amount of 0.01 to 3 parts based on 100 parts of vinyl chloride monomer and depends on the degree of polymerization and glossiness required.

In the present invention, in addition to the crosslinking agent commonly used in the polymerization of vinyl chloride resin, a silane-based crosslinking agent is used together to maintain the matting effect regardless of the change in molding conditions. The used silane crosslinking agent is the same as the following Chemical Formula 1, and the amount of the silane-based crosslinking agent is used in an amount of 0.005 to 2 parts based on 100 parts of the vinyl chloride monomer.

[Formula 1]

Wherein R ¹ , R ² , and R ³ are alkyl groups; X is -CO _2- ; m is 0 or 1 n and p is 0 or an integer; Y is -OCH ₂ , -OCH ₂ CH ₃ , -OCH ₂ CH ₂ CH ₂ , -OCH (CH ₃ ) ₂ , -OCH ₂ CH ₂ OCH ₃ or -OCOCH ₃ ; q represents 1, 2 or 3)

When two or more crosslinking agents including a vinyl chloride monomer and a silane crosslinking agent are copolymerized, the silane crosslinking agent is introduced into the branch having an alcoholic silane group in the vinyl chloride resin molecule in the polymerization stage. However, during the polymerization reaction, since the alkoxysilane group is present in the vinyl chloride monomer and the reaction temperature is low, it is difficult to form a bond through the condensation reaction between the alkoxysilane groups. Therefore, it can be said that the crosslinking reaction occurring during the polymerization reaction is mostly caused by the crosslinking agent used together. However, in the forming step, a bond is formed between the alkoxysilane group by a hydrolysis reaction and a condensation reaction, and the vinyl chloride resin is crosslinked. The more moisture present, the easier the bond between the alkoxysilane groups. In the case of general vinyl chloride resin or conventional crosslinked matte resin, when the molding proceeds, the vinyl chloride resin particles are gradually collapsed, and some of them are melted, and the gloss of the molded product is increased or the existing crosslinking agent and the alkoxysilane-based crosslinking agent are used. When used together, a new crosslinking reaction occurs between the vinyl chloride resin molecules by the condensation reaction during processing, thereby relatively lowering the particle disintegration and melting rate of the resin, thereby maintaining a relatively low gloss effect.

Dispersants used in the polymerization of crosslinked matte resins are similar to those of ordinary vinyl chloride resins. As the primary dispersant, cellulose-based and partially hydrated polyvinyl alcohols such as water-soluble methyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose and hydroxypropyl methyl cellulose are mainly used. Polyacrylic acid, gelatin, sorbitan monolaurate , Sorbitan trioleate, glycerin tristearate, ethylene oxide-propylene oxide block copolymer, polyoxyethylene sorbitan monolaurate, polyoxyethylene glycerine oleate and the like are also partially used. The primary dispersant is used in an amount of 0.005 to 2 parts based on 100 parts of the vinyl chloride monomer. Unlike the primary dispersant having a high degree of hydration and strong hydrophilicity, the secondary dispersant has a strong hydrophobicity. In the case of PVA used as a typical propellant, the hydrophilicity increases as the degree of hydration increases. PVA having a degree of hydration of 30% is soluble in vinyl chloride monomer but not soluble in water, and PVA with a degree of hydration of 55% is soluble in vinyl chloride monomer and partially soluble in water. PVA with a degree of hydration of 72.5% is completely soluble in water and therefore difficult to apply as a secondary dispersant. PVA-based dispersant used as the secondary dispersant is 70% or less hydration, the smaller the degree of hydration is more effective, especially PVA having a degree of hydration of 59% or less. Dispersants that have strong hydrophobicity and do not contain ethylene oxide repeating units are also useful as secondary dispersants, such as sorbitan esters, glycerol esters or polyglycerol esters. Sorbitan trioleate, sorbtan tristearate, sorbitan monooleate, sorbitan monopalmitate, glycerol monooleate, glycerol monostearate and triglycerol monooleate, mainly used and these compounds alone or in combination Used as secondary dispersant. These secondary dispersants serve to increase the voids of the resin particles and to increase the stability of the particles in the suspended state. Secondary dispersants are mainly used in an amount of 0.005 to 1 part with respect to 100 parts of vinyl chloride monomer, especially in the range of 0.1 to 0.5 parts.

As an initiator, diisopropyl peroxy dicarbonate, di-2-ethylhexyl peroxy dicarbonate, diethoxy ethyl peroxy dicarbonate, t-butyl peroxy pivalate, t-butyl peroxy neodecanate, α-cumylperoxyneodecanate, acetylcyclohexylsulfonylperoxide, 2,4,4-trimethylpentyl-2-peroxyphenoxyacetate and azo-bis-2,4-dimethylvaleronitrile 0.001-0.5 parts are used with respect to 100 parts of vinyl monomers.

The neutralization temperature of crosslinked matte resin is 30 ~ 75 ℃ and other polymerization conditions are similar to those of general vinyl chloride resin.

Comparative Example 1

200 parts of deionized water, 0.1 parts of polyvinyl alcohol having a degree of hydration of 90% as a dispersant, and 0.03 parts of dioctyl peroxydicarbonate as an initiator are added to a 200 L stainless polymerization reactor. Thereafter, the polymerization reactor was sealed, residual air was removed, and 100 parts of vinyl chloride monomer was added to the polymerization reactor. The polymerization temperature was maintained at 57 ℃ and the conversion was to be 85 ~ 9%. After removing the unreacted monomer, the polymerization product was dried after dehydration.

Heavy vinyl chloride resin has properties similar to those of general vinyl chloride resin having a degree of polymerization of 1000. The gloss measurement shows high glossiness from the beginning of processing and does not change much after the processing time has elapsed.

The experimental method of each physical property shown in the result is as follows.

Fusion time measurement

100 parts of resin, 5 parts of plasticizer, 2 parts of stabilizer, and 0.3 part of lubricant are mixed and measured using a roller mixer plasticoder. Experimental conditions were 30 rpm and 185 ° C. The melt time is defined as the time between the point at which the resin mixture is put into the roller mixer and the equilibrium state is reached, which indicates the maximum torque.

Fish-eye

100 parts of resin, 50 parts of plasticizer, 2 parts of stabilizer and 0.05 parts of carbon black were mixed and processed for 8 minutes in a 150-degree two-roll mill to make a sheet having a thickness of 0.2 mm. -Measure the number of children.

Gel content measurement

After dissolving 0.5 g of the resin in 25 ml of THF for 24 hours, the gel portion not dissolved in THF is separated using a centrifuge (10000 rpm, 1 hr). The separated gel was washed with THF and dried at 50 ° C. in a vacuum for at least 10 hours. The gel content is obtained by dividing the weight of the dry gel portion by the initial sample weight and converting it to a percentage.

Gloss measurement

After mixing 100 parts of resin, 30 parts of plasticizer and 3 parts of stabilizer, the sheet is formed using a double roll mill having a surface temperature of 180 ° C. After 3, 5 and 10 minutes, the specimens are taken and the gloss is measured. The measurement was carried out at 45 degrees, and the glossiness of the standard black plate was 87.9%.

Comparative Example 2

Diallylphthalate (DAP) was used at 0.4 part with respect to 100 parts of vinyl chloride monomer. Conditions other than this are the same as that of the comparative example 1.

When crosslinking the vinyl chloride resin using DAP as a crosslinking agent, it can be observed that the melting time, gel content and fish-eye increase rapidly. Glossiness Compared with Comparative Example 1, the glossiness is considerably lowered throughout the processing, but the glossiness increases as the processing proceeds.

Comparative Example 3

0.3 part of diallylphthalate (DAP) and 0.2 part of triacetoxysilylethylene (TASE) were used with respect to 100 parts of vinyl chloride monomers. Conditions other than this are the same as that of the comparative example 1.

Table 1 shows the results of mixing DAP and TASE as crosslinking agents. The amount of DAP was lower than that of Comparative Example 2. The gel content was similar to Comparative Example 2 but the melting time and fish-eye were reduced to a significant extent. In particular, the initial glossiness in the glossiness result is higher than in the case of Comparative Example 2, but as the processing proceeds, the degree of gloss increase is small, and in the latter half of the process, the result is lower than that of Comparative Example 2.

Comparative Example 4

0.4 parts of diallylphthalene (DAP) and 0.05 parts of polyvinyl alcohol having a degree of hydration of 42% were used for 100 parts of vinyl chloride monomer. Other conditions were the same as in Comparative Example 1.

Using DAP as a crosslinking agent and PVA having a degree of hydration of 42% as a secondary dispersant, the pores of the crosslinking resin were increased to improve the workability. Compared with the results of Comparative Example 2 without the use of a secondary dispersant, it can be seen that the melt time and the fish-eye are significantly reduced. The glossiness change of the sheet according to the processing step is similar to the result of Comparative Example 2.

Example 1

0.3 parts of diallylphthalate (DAP), 0.2 parts of TASE and 0.05 parts of polyvinyl alcohol having a degree of hydration of 42% were used for 100 parts of vinyl chloride monomer. Other conditions are the same as in Comparative Example 1.

Using DAP and TASE as a crosslinking agent and PVA with 42% hydration as a secondary dispersant, the melt time and fish-eyes were significantly reduced compared to Comparative Example 3 using only DAP and TASE. Was similar.

Example 2

0.3 part of diallyl phthalate (DAP), 0.2 part of TASE and 0.1 part of polyvinyl alcohol having a degree of hydration of 42% were used with respect to 100 parts of vinyl chloride monomers. Conditions other than this are the same as that of the comparative example 1.

The melt time and the fish-eye were greatly reduced when the secondary dispersant was used more than Example 1.

Example 3

0.3 part of diallylphthalate (DAP), 0.2 part of TASE and 0.1 part of sorbitan monolaurate were used for 100 parts of vinyl chloride monomer. Conditions other than this are the same as that of the comparative example 1.

It can be observed that the use of sorbitan monolaurate as the secondary dispersant results in a significantly lower melting time and fish-eye than in the case of the use of PVA. The gel content and the degree of glossiness change of the processed specimens were generally similar.

Example 4

0.3 part of diallylphthalate (DAP), 0.2 part of TASE and 0.1 part of sorbitan trioleate were used for 100 parts of vinyl chloride monomer. Conditions other than this are the same as that of the comparative example 1.

Even when sorbitan trioleate is used as the secondary dispersant, reduction of melting time and fish-eye can be observed.

TABLE 1

In the crosslinking matt vinyl chloride resin manufacturing method, by using two or more kinds of crosslinking agents including a silane crosslinking agent and a secondary dispersant as a crosslinking agent, matte chloride excellent in maintaining a constant glossiness, processing time with reduced melt time and fish-eye Vinyl resin can be manufactured.

Claims (4)

In preparing a vinyl chloride-based resin mainly composed of a vinyl chloride monomer, 0.01 to 3 parts or more of two or more kinds of crosslinking agents including a silane-based crosslinking agent having a structure of 0.005 to 2 parts by weight of a crosslinking agent with respect to 100 parts of vinyl chloride monomer as follows: Tea dispersants 0.005-2 parts, sorbitan tristearate, sorbitan trioleate, sorbitan monooleate, sorbitan monopalmitate, glycelomonolate, glycerol monostearate, triglycerol monooleate and Method for producing a matte vinyl chloride resin, characterized in that 0.005 to 1 part of a secondary dispersant selected from the group consisting of PVA having a degree of hydration of 50% or less and 0.001 to 0.5 part of an initiator, and having a polymerization temperature of 30 to 75 ° C. [Formula 1]

Wherein R ¹ , R ² , and R ³ are alkyl groups; X is -CO _2- ; m is 0 or 1; n and p are 0 or an integer; Y is -OCH ₃ , -OCH ₂ CH ₃ , -OCH ₂ CH ₂ CH ₃ , -OCH (CH ₃ ) ₂ , -OCH ₂ CH ₂ OCH ₃ or -OCOCH ₃ ; q represents 1, 2 or 3). The crosslinking agent according to claim 1, wherein the crosslinking agent used in combination with the silane-based crosslinking agent is diallyl phthalate, diallyl terephthalate, diallyl maleate, diallyl fumarate, diallyl itaconate, diallyl adipate, diallyl ether, trially Allyl cyanurate, triallyl isocyanurate, ethylene glycol divinyl ether, n-butanediol divinyl ether, octadecane divinyl ether, vinyl acrylate, vinyl methacrylate, allyl acrylate, allyl methacrylate, ethylene Glycol diacrylate, ethylene glycol dimethacrylate, triethyl glycol dimethacrylate, diethylene glycol diacrylate, triethylene glycol diacrylate, polyethylene glycol diacrylate, polyethylene glycol bis (allylcarbonate), trimethyl Group consisting of all propane trimethacrylate and trimethylolpropane triacrylate A method characterized in that selected from. The method according to claim 1, wherein the secondary dispersant is used in an amount of 0.005 to 1 part based on 100 parts of vinyl chloride monomer. The method according to claim 3, wherein the secondary dispersant is used in an amount of 0.1 to 0.5 parts based on 100 parts of the vinyl chloride monomer.