KR20110070016A - Method of preparing vinyl chloride paste resin having good thermal stability - Google Patents

Abstract

PURPOSE: A method for preparing a paste vinyl chloride-based resin is provided to improve thermal stability of a paste vinyl chloride-based resin itself and to suppress the coloring by the heat in wallpaper foaming processing. CONSTITUTION: A method for preparing a paste vinyl chloride-based resin comprises a step of adding a basic compound with pH 8 - 10 in post reaction polymerization of the paste vinyl chloride-based resin. The amount of the basic compound is 0.001~0.6 parts by weight based on the weight of a vinyl chloride monomer. The basic compound is light ash(Na2CO3).

Description

Method of preparing vinyl chloride paste resin having good thermal stability

The present invention relates to a method for producing a paste vinyl chloride-based resin, which is prepared by adding tracing to the late stage of the polymerization reaction of the paste-vinyl chloride-based resin, and has excellent thermal stability, so that coloring due to heat does not occur when preparing the foamed wallpaper.

Vinyl chloride-based resin is excellent in flame retardancy or chemical resistance, but it is easily decomposed by heat, causing dehydrogen chloride reaction to weaken mechanical strength, and coloring causes damage to the product's marketability. Such degradation or coloring is known to be due to the formation of a polyene structure by a dehydrochlorination reaction.

In the vinyl wallpaper manufacturing process, an appropriate amount of a paste vinyl chloride resin, a plasticizer, a filler, a foaming agent, a stabilizer, a viscosity reducing agent, and the like are added and mixed as necessary to obtain a plastisol. The plastisol is coated on paper (coated paper) about 50-200 μm, and then first gelled at 130-180 ° C., and secondly gelled at 180-250 ° C. to obtain a foam sheet. After that, the foam sheet is printed and embossed to obtain a final wallpaper product. The most important of such wallpaper foam products is the surface and whiteness of the product, the size and uniformity of the foam cells.

Since the vinyl wallpaper product is foamed at a high temperature, 1 to 10 parts by weight of a stabilizer is added to the plastisol. If the stabilizer is not added, the foamed product may be colored yellow or black by dehydrochlorination. However, stabilizers do not use more than 3 to 5 parts by weight because of excessive use as a volatile organic compound causes indoor environmental pollution problems. As described above, the conventional technology has improved the coloring by heat by adding a stabilizer, but there was no limit other than the stabilizer.

In order to solve the problems of the prior art as described above, an object of the present invention is to provide a method for producing a paste vinyl chloride-based resin having excellent thermal stability that does not occur coloring by heat during the production of vinyl wallpaper.

In the present invention, it is possible to solve the problem of coloring by heat by adding tungsten as a basic compound having a pH of 8 to 10 at the end of the polymerization reaction in the preparation of the paste vinyl chloride resin used for wallpaper production.

The present invention improves the thermal stability of the paste vinyl chloride-based resin itself, and has the advantage that the foaming processing area is wide as well as the effect of inhibiting coloring due to heat during wallpaper foaming. Therefore, the paste vinyl chloride-based resin prepared according to the present invention can be widely used for wallpaper, material, leather processing, etc., in which thermal stability is important.

In order to achieve the above object, the manufacturing method of the paste vinyl chloride-based resin according to the present invention is the step of adding the Gyeong (Na ₂ CO ₃ ) as a basic compound having a pH of 8 to 10 after the reaction polymerization of the paste vinyl chloride-based resin Characterized in that it comprises a.

Hereinafter, the present invention will be described in detail.

The method for preparing a paste vinyl chloride-based resin of the present invention is based on a vinyl chloride monomer, a seed latex, an emulsifier, a polymerization initiator, and an aliphatic molecular chain having 12 or more carbon atoms having a lubricating property in an aqueous medium. The polymerization is carried out by adding a compound having a polar group, but adding a basic compound satisfying a specific pH at the end of the reaction polymerization.

As the polymerization method of the paste vinyl chloride-based resin, microsuspension polymerization, emulsion polymerization or seed emulsion polymerization may be used.

The present invention is to improve the thermal stability by adding a basic compound of pH 8 ~ 10 at the end of the polymerization reaction for producing a paste vinyl chloride resin using one method selected from the above fine suspension polymerization, emulsion polymerization or seed emulsion polymerization There is one characteristic.

As the basic compound, sodium carbonate (Na ₂ CO ₃ ), which is preferably called light, soda ash and the like.

Conventionally, sodium hydroxide was used as the basic compound, and the pH of the sodium hydroxide belongs to a strong base of about 12 to 13 degrees. When the sodium hydroxide is used as the basic compound, it is preferably used in an amount of 0.008 to 0.04 parts by weight, more preferably 0.01 to 0.03 parts by weight, and most preferably 0.03 parts by weight based on the weight of the vinyl chloride monomer (VCM). If the amount is less than 0.008 parts by weight, the effect of addition is insignificant, and if it exceeds 0.04 parts by weight, sodium hydroxide is a strong base, which causes latex stability to decrease and cause aggregation. However, in order to see the desirable effect of sodium hydroxide should be added to about 0.03 parts by weight, when added in excess of this latex aggregation occurs there was a limit to use. Therefore, in the case of the relatively strong base sodium hydroxide was not able to solve the problem caused by the limitation of the content in actual use.

On the contrary, in the case of light (Na ₂ CO ₃ ), which is a basic compound according to the present invention, 0.001 to 0.6 parts by weight, preferably 0.02 to 0.4 parts by weight, based on the weight of vinyl chloride monomer (VCM) used as pH 8-10. Most preferably 0.5 parts by weight. If the amount is less than 0.001 part by weight, the addition effect is insignificant, and if it exceeds 0.6 parts by weight, the effect of improving the thermal stability due to the addition is insignificant and there is a concern that the latex stability may be lowered.

This is a wide range of the amount of use that can effectively improve the thermal stability compared to the sodium hydroxide used in the prior art is preferable to use after addition.

The addition state of the basic compound is not particularly limited, but is preferably an aqueous solution mixed with water, for example, in the case of light (Na ₂ CO ₃ ) 5 to 10% by weight of the aqueous solution, preferably 5 It may be added in an aqueous solution of% by weight, if the concentration of the aqueous solution is too high there is a fear that the stability of the latex is lowered.

In the present invention, the time point of adding the basic compound of light chain is defined as the late stage of the reaction polymerization, where “reaction late polymerization” is meant to include the end point of the polymerization, and specifically, the reactor pressure is 3.0 to 4 kgf /. It is the time of cm <^2> and as a polymerization conversion rate of a monomer, it is 80% or more, Preferably it is 80-98%, More preferably, it is 95-98%.

 If the basic compound according to the present invention is not added to the late stage of the reaction polymerization as described above, and the pH of the reactant is increased at the initial stage of the polymerization, the activity of the initiator is lowered, the polymerization reaction may not be performed smoothly. It is preferable to add at the end of reaction polymerization.

The paste vinyl chloride resin according to the present invention has 1 to 10 parts by weight of the latex particle latex, within 1 part by weight of the emulsifier, 0.001 to 2.0 parts by weight of the polymerization initiator, and 12 carbon atoms having lubricating properties with respect to 100 parts by weight of the vinyl chloride monomer. The above aliphatic molecular chain may be prepared by adding 0.1 to 3.0 parts by weight of a compound having a basic skeleton and a polar group.

The vinyl chloride monomer can be used alone or in combination with other copolymerizable monomers. Examples of the copolymerizable monomer include olefins such as ethylene, propylene and butene; Vinyl esters of carboxylic acids such as vinyl acetate, vinyl propionate and vinyl stearate; Vinyl ethers having alkyl groups such as methyl vinyl ether, ethyl vinyl ether, octyl vinyl ether, and lauryl vinyl ether; Vinylidene halides such as vinylidene chloride; Unsaturated carboxylic acids such as acrylic acid, methacrylic acid, fumaric acid, maleic acid, itaconic acid, maleic anhydride and itaconic anhydride and acid anhydrides thereof; Unsaturated carboxylic acid esters such as methyl acrylate, ethyl acrylate, monomethyl maleate, dimethyl maleate, and butylbenzyl maleate; Aromatic vinyl compounds such as styrene, α-methyl styrene and divinyl benzene; Unsaturated nitriles such as acrylonitrile; Or crosslinkable monomers, such as diallyl phthalate, etc. can be used individually or in mixture of 2 or more types. In this case, the copolymerizable monomer is preferably used in a maximum of 50 parts by weight of 100 parts by weight of the total monomers. When the amount is included within a maximum of 50 parts by weight, the polymerization is stable, excellent dispersibility to the plasticizer of the paste vinyl chloride-based resin has the effect of improving the workability.

The seed particle latex (seed latex) may be used by mixing one or more species seed particle latex different in size. In particular, it is preferable to mix and use the seedling particle latex whose average particle diameter is 0.1-0.22 micrometer, and the seedling particle latex whose average particle diameter is 0.4-0.66micrometer. It is not possible to say that the seedling particles having a certain average particle size are preferable because the final latex particle size distribution may be changed by adjusting the dosage used in the present polymerization.

The latex particle latex (40% solids content) according to the present invention is preferably used in an amount of 1 to 10 parts by weight based on 100 parts by weight of the vinyl chloride monomer. When the amount is 1 to 10 parts by weight, the polymerization reactivity is excellent, control of the heat of reaction is easy, and productivity is improved.

The emulsifier may be one or more selected from the group consisting of alkyl sulfates, anion emulsifiers, polyethylene glycols and derivatives thereof, and polyepropylene glycols and derivatives thereof. The anionic emulsifier may be selected from the group consisting of carboxylic acid, alkyl sulfonic acid, alkyl benzene sulfonic acid, sulfo succinic acid, α-olefin sulfonic acid, and alkyl phosphoric acid. The emulsifier may be used up to 1 part by weight based on 100 parts by weight of the vinyl chloride monomer.

When the amount is used within a maximum of 1 part by weight, the mechanical stability of the latex polymerized is excellent. The emulsifier may be added in an aqueous medium before the polymerization reaction, may be continuously added to the aqueous medium during the polymerization reaction, may be added to the latex after the polymerization reaction is completed, it can be used in combination with the above method if necessary.

Examples of the polymerization initiator include peroxy dicarbonates, such as diisopropyl peroxy dicarbonate, in the case of fine suspension polymerization; organic peroxide initiators such as peroxy esters such as t-butyl pearloxy pivalate and t-butyl pearl oxy neodecanoate, or azo (azo) such as 2,2-azobisisobutyronitrile. ) Initiator or the like can be used alone or in combination.

In addition, in the case of emulsion polymerization or seed emulsion polymerization, ammonium persulfate, potassium persulfate, sodium persulfate or hydrogen peroxide can be used as a water-soluble polymerization initiator, and sodium sulfite, sodium, ascorbic acid, etc. as necessary. Can be used together.

The polymerization initiator is preferably used in 0.001 to 2.0 parts by weight based on 100 parts by weight of the vinyl chloride monomer. When the amount is 0.001 to 2.0 parts by weight, the polymerization reactivity is excellent, and the heat of reaction can be easily controlled.

Specific examples of the compound having a polar group based on an aliphatic molecular chain having 12 or more carbon atoms of the present invention include a higher alcohol such as cetyl alcohol, lauryl alcohol, mystic alcohol, stearyl alcohol; Higher fatty acids such as lauric acid, myristic acid, parmitic acid, stearic acid, and esters thereof; Aromatic hydrocarbons; Higher fatty acid hydrocarbons; Halogen hydrocarbons such as chlorinated paraffin; Triacylglycerols; Other short-chain alcohols; Fatty acid amides such as bis (stearoyl) ethylene diimine; Or a metallic soap may be used.

The compound having a basic skeleton having an aliphatic molecular chain of 12 or more carbon atoms and having a polar group is preferably used in an amount of 0.1 to 3 parts by weight, and more preferably 0.5 to 2.5 parts by weight, based on 100 parts by weight of the vinyl chloride monomer. If the amount is less than 0.1 part by weight, the viscosity stability of the plastisol at room temperature and high temperature is not maintained. If the amount is more than 3 parts by weight, the polymerization stability at the time of manufacture is weakened or the compound is transferred from the final molded product to shrink the molded product. There is a problem that a defect occurs such as. The compound having a basic skeleton having an aliphatic molecular chain of 12 or more carbon atoms and having a polar group may be added together with a vinyl chloride monomer, latex particle latex, an emulsifier, and a polymerization initiator at the beginning of the reaction, or may be added alone at a later stage of the reaction. .

The reaction temperature of this step is determined in consideration of the reaction rate, the boiling point of the solvent, and the like, when water is a solvent, for example, may be 25 to 90 ℃, more specifically 61 ℃.

The reaction pressure is determined in consideration of the reaction temperature, the boiling point of the solvent, and the like. The reaction time is not particularly limited, too short if the reaction yield is low, too long is uneconomical without particular advantages.

The vinyl chloride paste resin prepared in this step is obtained as a reaction product on a latex, and the obtained reaction product can be prepared as a paste resin in the form of a powder by a conventional method. The paste resin latex may be carried out by a process of spray drying. In this case, it can be dried without performing processes, such as dehydration and filtration, In this case, raw materials, such as an emulsifier, remain in the final vinyl chloride paste resin.

The vinyl chloride paste resin prepared according to the present invention may be mixed with a plasticizer, a foaming agent, a viscosity reducing agent, a heat stabilizer, and other additives to form a plastisol.

Examples of the plasticizer include dioctylphthalate, 2,2,4-trimethyl-1,3-pentanediol diisobutyrate (2,2,4-trimethyl-1,3- 5-pentanediol diisobutyrate), TXIB, and the like. Examples of the blowing agent include aliphatic hydrocarbons such as propane, isobutane, normal butane, isopentane and normal pentane; Cyclic aliphatic hydrocarbons such as cyclopentane and cyclohexane; Halogenated hydrocarbon compounds; Or a mixture thereof can be illustrated, Ba-Zn-based stearate can be illustrated as a heat stabilizer.

The vinyl chloride paste resin prepared according to the present invention has an advantage of excellent thermal stability, which does not cause coloring due to heat when forming molded articles such as foamed wall paper, and has a wide foam processing area, so that wallpaper, material, and leather are important for thermal stability. There is an advantage that can be widely used for processing.

Hereinafter, the present invention will be described in more detail with reference to Examples, but the scope of the present invention is not limited by Examples.

Example 1

In a 200 L high-pressure reactor, 54 kg of deionized water, 1 g of potassium persulfate as a polymerization initiator, 40% of solids, 40% of solid content, and 0.19 μm mean particle latex 4.8 kg and 40% of solid content, 0.66 μm mean particle latex 8.0 kg was added and then vacuum was applied to the reactor while stirring. 77 kg of a vinyl chloride monomer was added to a reactor in a vacuum state, and then the temperature of the reactor was raised to 61 ° C and polymerized. When the polymerization was started, 10.4 kg of a 5% aqueous solution of lauryl sulfate sodium salt was continuously added to the reactor for 4 hours as an emulsifier. Next, after removing the When the pressure of the reactor reached 4㎏ / ㎠ In the 5% gyeonghoe (Na ₂ CO ₃₎ aqueous solution of 1.54 kg (pH 9) and allowed to cool and then stirred for 20 minutes and recovering the unreacted vinyl chloride monomer, Spray drying was performed to prepare a powdery paste vinyl chloride resin.

[Example 2]

Powdered paste vinyl chloride resin was prepared in the same manner as in Example 1, except that 1.16 kg (pH 9) of 5% aqueous Na ₂ CO ₃ solution was added.

Example 3

A powdery paste vinyl chloride resin was prepared in the same manner as in Example 1, except that 0.77 kg (pH 9) of a 5% aqueous Na ₂ CO ₃ solution was added.

[Comparative Example 1]

Powder paste vinyl chloride resin was prepared in the same manner as in Example 1, except that 5% aqueous solution of Na ₂ CO ₃ was not added.

Comparative Example 2

A powdery paste vinyl chloride resin was prepared in the same manner as in Example 1, except that sodium hydroxide (pH 12) was added at 0.02 part by weight in place of the 5% aqueous Na ₂ CO ₃ solution in Example 1. Prepared.

Comparative Example 3

Powder paste vinyl chloride resin was prepared in the same manner as in Example 1, except that 0.03 parts by weight of sodium hydroxide was added instead of the 5% aqueous Na ₂ CO ₃ solution in Example 1.

Experimental Example

Powdered paste vinyl chloride resin prepared according to the Examples and Comparative Examples to prepare a plastisol as follows, the physical properties were evaluated, the results are shown in Table 1 below.

1) Preparation of Plastisol

75 parts by weight of dioctylphthalate, 100 parts by weight of calcium carbonate, 12.5 parts by weight of TiO2, 3 parts by weight of blowing agent, 13 parts by weight of viscosity reducing agent, stabilizer (Ba-Zn type stearate) After adding the parts by weight, 10 minutes at 500 rpm, 10 minutes at 800 rpm was mixed to prepare a plassol.

2) viscosity measurement

The plastisol prepared above was aged for 1 hour in a 25 ° C. constant temperature oven, and the viscosity was measured using a BrookField viscometer (rotation speed 6 rpm).

3) Foam sheet production

The plastisol was coated on a paper with a 0.54 mm coater and then foamed at a Mathis oven (THERMOTESTER LTE-T) temperature 150 ° C. for 40 seconds to make a semi-finished product. The semi-finished sheet was cut to a suitable size and foamed for 3, 4, 5, 6, and 7 minutes at a Mathis oven temperature of 200 ° C. to produce a finished foam sheet.

4) Thermal stability measurement

The whiteness of the finished foam sheet (3, 4, 5, 6, 7 minute sheet at a Mathis oven temperature of 200 ° C.) prepared above was measured to determine how colored by heat. In general, the thermal stability measured the whiteness at about 5 minutes the sheet is discolored, but the whiteness was measured up to 7 minutes to see the point of discoloration because the thermal stability was improved by adding a race.

division Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2 Comparative Example 3 BF Viscosity (cP) 4050 4050 4060 4070 4080 5100 Latex pH 10.5 9.6 8.8 6.3 10.5 10.9 Foam thermal stability measurement
(200 ℃ finished product) 3 minutes whiteness 70 69 69 69 69 70 4 minutes whiteness 59 54 50 39 49 51 5 minutes whiteness 48 35 12 -2 9 19 6 minutes whiteness 19 -One -20 -38 -15 2 7 minutes whiteness 8 -45 -48 -49 -45 -44

Through the results of Table 1, invention example and as gyeonghoe (Na ₂ CO ₃₎ for Comparative Example 1 compared gyeonghoe the results of up to 5 minutes conventional whiteness test range, and the addition to the reaction late without addition of gyeonghoe As the dosage increased, it was confirmed that the thermal stability was improved. In addition, the whiteness was measured up to 7 minutes to determine the time of discoloration of the foam sheet according to the present invention.

In addition, the color change of the foam sheet experimented with the thermal stability of the Example and Comparative Example is shown in Figure 1 below. It can be confirmed that the color change of the foam sheet according to the present invention is excellent compared to Comparative Example 1 without adding the tungsten, or Comparative Examples 2 and 3 with the addition of sodium hydroxide. In particular, in the case of Comparative Example 3 in which the maximum amount that can be added using the conventional sodium hydroxide as the basic compound was found to show a similar result to Example 3 of the present invention, in this case, instantaneous latex flocculation by the addition of sodium hydroxide. As a result, latex particles form agglomerates (agglomerate), which cause undesirable viscosity increase in subsequent plastisol preparation.

Therefore, it was confirmed that the use of hardening in terms of the stability and thermal stability of the latex exhibits an improved effect than the use of sodium hydroxide whose use is extremely limited as in the prior art.

Figure 1 shows the color change of the foam sheet prepared by the plastic chloride prepared according to the Examples and Comparative Examples and then tested for thermal stability.

Claims (6)

A method for producing a paste vinyl chloride-based resin, comprising the step of adding a basic compound having a pH of 8 to 10 at the end of the reaction polymerization of the paste-vinyl chloride-based resin. The method of claim 1, wherein the basic compound is added in an amount of 0.001 to 0.6 parts by weight based on the weight of the vinyl chloride monomer. The method of manufacturing a paste vinyl chloride-based resin according to claim 1, wherein the basic compound is hard (Na ₂ CO ₃ ). The method of claim 1, wherein the late polymerization stage is a time point at which the reactor pressure is 3.0 to 4.0 kgf / cm ² . The method for producing a paste of vinyl chloride-based resin according to claim 1, wherein the late polymerization stage is a time point at which the polymerization conversion rate of the monomer is 80 to 98%. Molded article made of a paste vinyl chloride resin prepared by the method according to claim 1.

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