KR100359878B1 - Preparation method of vinyl chloride-based resin with excellent heating discoloration resistance - Google Patents

Abstract

PURPOSE: A method for preparing a vinyl chloride-based resin for paste processing and a vinyl chloride-based resin prepared by the method are provided, to improve the heating discoloration resistance. CONSTITUTION: The method comprises the steps of adding 5-30 parts by weight of two kinds of latex particles with different size used as a seed particle for an alkali metal salt of alkyl benzene sulfonate of C10-C30 and a vinyl chloride resin, to 100 parts by weight of a vinyl chloride monomer, and homogenizing the mixture with an organic peroxide and water to polymerize them; and adding 0.5-10 parts by weight of a poly(vinyl alcohol)-based resin whose degree of hydration is 20-50 parts by weight to the obtained latex, and spray drying the obtained one to prepare the vinyl chloride-based resin. Preferably the alkali metal salt of alkyl benzene sulfonate of C10-C30 is sodium salt of dodecyl benzene sulfonate.

Description

Manufacturing method of vinyl chloride-based resin excellent in heat discoloration

Vinyl chloride-based resins for paste processing are general purpose resins for a wide range of applications in everyday life products and industries such as architectural flooring, wallpaper, artificial leather, woven coatings, sheets, packaging and agricultural films. Paste vinyl chloride-based resins are usually produced by mixing with a plasticizer to prepare a paste sol, followed by a process forming process in a temperature range significantly higher than the degradation temperature of the resin. Due to the high processing and molding temperature conditions of the vinyl chloride-based resin for paste processing or the deterioration due to heat, light, and moisture according to the environment of using the synthetic resin, hydrogen chloride in the resin constituents is released and an unsaturated bond structure is formed in the chain to discolor the resin. There is a problem that the phenomenon occurs, this coloring phenomenon is called heat discoloration phenomenon.

Hydrogen chloride is generated when the vinyl chloride-based resin is decomposed by heat, and the generated hydrogen chloride serves as a catalyst for promoting the decomposition of the vinyl chloride-based resin, so the heat discoloration of the resin is closely related to the rapid removal of hydrogen chloride. There is. In this regard, a technique of using an organometallic stabilizer is known as a method for suppressing heat discoloration of a paste vinyl chloride-based resin.However, when only an organometallic stabilizer is used, the heat discoloration phenomenon is induced by entraining hydrogen chloride. Although it can be delayed, the problem of heating discoloration does not fundamentally solve the problem of heating discoloration is worse than heating rather than a certain limit, and the use of metal-based stabilizers in recent years in relation to the environmental problems are significantly limited.

In order to suppress the heat discoloration of the paste vinyl chloride-based resin, a vinyl chloride-based resin latex polymerized by a conventional method is mixed with a water-soluble polymer to prepare a paste sol with a dry resin, and thus, a vinyl chloride-based resin for paste processing having excellent heat discoloration inhibiting ability. It was confirmed that the preparation can be completed the present invention.

The content of the present invention will be described in detail below.

First, 5 to 30 parts by weight of a mixture of a vinyl chloride monomer or a copolymerizable monomer with vinyl chloride monomer and two different latex particles having different sizes and alkali metal salts of alkylbenzenesulfonate having 10 to 30 carbon atoms By adding the polyvinyl alcohol-based resin having a degree of hydration of about 30 parts by weight to the latex obtained after polymerization by homogenization with organic peroxide and water, 0.5-10 parts by weight of the latex was mixed and spray-dried by a conventional method to obtain a resin in powder form. Get

In the present invention, the vinyl chloride resin means a resin having a vinyl chloride content of 70% or more by weight in the total resin composition. Monomers copolymerizable with vinyl chloride monomers include vinyl acetate, acrylates, methacrylates, olefins such as ethylene and propylene, unsaturated fatty acids such as acrylic acid, methacrylic acid, itaconic acid and maleic acid, and anhydrides of these fatty acids. Generally, these are those used in the conventional method of copolymerizing vinyl chloride.

In the present invention, two kinds of latex particle latexes used as seedling particles for preparing a paste vinyl chloride-based resin may be added in an amount of 2 to 10 parts by weight, respectively, with respect to the vinyl chloride monomer weight ratio in a solid component ratio of 40%. In addition, an anionic emulsifier having 10 to 30 carbon atoms is added as a continuous input emulsifier for stabilization of the manufacturing process according to the growth of the seedling particles. Alkylbenzenesulfonate alkali metal salts are suitable as the emulsifier usable for the purpose of the present invention. Preferably, a C10-C16 linear alkylsulfonate or sulfate salt can be used.

The catalyst which can be used for the microsuspension polymerization or the deep microsuspension polymerization reaction of the present invention includes an organic peroxide. Specific examples of organic peroxide catalysts

Diacyl peroxides such as dipentyl peroxide, di-3, 5, 5-trimethyl hexanoyl peroxide and dilauroyl peroxide;

Peroxydicarbonates such as diisopropyl peroxydicarbonate, dibutyl butyl peroxydicarbonate and di-2-ethylhexyl peroxydicarbonate;

Peroxy esters such as tertiary butyl peroxy pivalate and tertiary butyl peroxy neodecanoate;

Azo compounds such as azobisisobutyronitrile, azobis2-methylbutyronitrile, azobis-2 and 4-dimethylvaleronitrile;

Or sulfates such as potassium persulfate and ammonium persulfate.

It is possible to use such an organic peroxide individually or in combination of 2 or more types.

The amount of initiator used is determined by factors such as manufacturing process, productivity, and quality. Generally, it is possible to use 0.5 to 2.0 parts by weight of initiator with respect to 100 parts by weight of total charged monomer, and preferably 0.8 to 1.5 parts by weight. desirable. When the amount of the initiator is excessively small, the reaction time is delayed and the productivity is lowered. When the amount of the initiator is excessively used, the initiator is not completely consumed during the polymerization process and remains in the final resin product to lower the thermal stability and color quality of the resin.

In order to improve the heat discoloration resistance of the vinyl chloride resin for paste processing in the present invention, polyvinyl chloride having a water solubility of 20 to 50 parts by weight as a water-soluble polymer in vinyl chloride resin latex is 0.5 to 3 parts by weight with respect to the vinyl chloride resin latex. Add to use. When polyvinyl chloride having a hydration degree lower than the above range is used, the effect of improving heat discoloration resistance is insignificant. When the polyvinyl chloride is higher than the above range, the discoloration improvement effect is excellent, but the viscosity of the sol is extremely poor and the transparency is poor during paste processing. Therefore, it is very important to select a polyvinyl alcohol having an appropriate degree of hydration.

The above-mentioned auxiliary raw materials are polymerized while stirring in a reactor, and 0.5-10 parts by weight of polyvinyl alcohol, which is a water-soluble polymer having a degree of hydration of about 30 parts by weight, is added to the latex obtained after the completion of the polymerization reaction and spray-dried by a conventional method.

Although the following Examples and Comparative Examples are shown to specifically illustrate the present invention, the present invention is not limited to these examples.

<Example 1>

1 m ^3, but is added to deionized water, 350 l into a dodecylbenzene sulfonate sodium salt, 15 parts by weight of the aqueous solution with stirring to 23 Kg pressure reactor, put 10 to 15 parts by weight of the first and the rest is added after the temperature was raised to 49 consecutive ℃ . 42 Kg and 30 Kg of the latex particle latex having a solid component ratio of 40 parts by weight of different sizes used as the seedling particles under vacuum were added, followed by 450 Kg of vinyl chloride monomer. After the reaction was completed, 1 parts by weight of polyvinyl alcohol having a degree of hydration of 30 parts by weight was mixed with 100 parts by weight of the latex to spray dried to obtain a powdered vinyl chloride resin in powder form.

Comparative Example 1

In Example 1, the vinyl latex resin was prepared by spray drying without adding polyvinyl alcohol-based resin to the final latex.

Comparative Example 2

In Example 1, 1 part by weight of polyvinyl alcohol having a degree of hydration of 80 parts by weight in the final latex was spray-dried to prepare a vinyl chloride resin.

Comparative Example 3

In Example 1, 1 part by weight of polyoxyethylene nonylphenyl ether added with 5 moles of ethylene oxide instead of the polyvinyl alcohol resin was added to the final latex to spray dry to prepare a vinyl chloride resin.

50 parts by weight of dioctylphthalate (DOP) and 1 part by weight of Ba / Zn-based stabilizer were added to 100 parts by weight of the paste vinyl chloride resin thus obtained, to prepare a paste sol, and a sheet having a thickness of 0.54 mm was formed, Heat discoloration resistance was measured in minutes.

<Heat discoloration test>

1. Sheet-Manufacture

A. Paste sol compounding method [part by weight]

Paste Vinyl Chloride Resin 100

Dioctylphthalate (DOP) 50

Bz / Zn Stabilizer 1.0

N. Sheet manufacturing

Sheet thickness 0.54 mm

Test temperature 200 ℃

3 minutes heating time

2. Discoloration test result

division Example Comparative Example 1 Comparative Example 2 Comparative Example 3 BF Viscosity DOP 40 [cps] 80,000 80,000 180,000 30,000 Yellow Degree (YI) 9.2 12.2 9.0 11.9 Whiteness (WI) 52 44 56 46 Discoloration test result after 3 minutes heating at 200

Claims (6)

5-30 parts by weight of two kinds of latex particles having different sizes used as alkali metal salts of alkyl bezel sulfonate having 10 to 30 carbon atoms and as seed particles of vinyl chloride resin are added to 100 parts by weight of vinyl chloride monomer, A method for producing a vinyl chloride resin for paste processing by a conventional spray drying method by adding 0.5 to 10 parts by weight of a polyvinyl alcohol resin having a degree of hydration of 20 to 50 parts by weight to a latex obtained by homogenization with a peroxide and water. The method according to claim 1, wherein 0.8 to 10 parts by weight of the polyvinyl alcohol resin having a degree of hydration of 30 parts by weight relative to the final vinyl chloride resin latex is added. The method of claim 1, wherein the monomer copolymerizable with vinyl chloride is used with vinyl chloride. The method of claim 1 wherein the alkali metal salt of alkyl benzene sulfonate is the sodium salt of dodecyl benzene sulfonate. The method according to claim 1, wherein the alkali metal of the alkyl benzene sulfonate is used in an amount of 0.5 to 3.0 parts by weight based on 100 parts by weight of the vinyl chloride monomer. A vinyl chloride resin for paste processing prepared by adding 0.5 to 10 parts by weight of a polyvinyl alcohol resin having a degree of hydration of 20 to 50 parts by weight to a vinyl chloride resin latex obtained by emulsion polymerization.