KR101009847B1 - Method for preparing polyvinyl-vinylacetate copolymer - Google Patents

Abstract

The present invention relates to a method for preparing a vinyl chloride-vinylacetate copolymer, more specifically, a) the maximum of 100 parts by weight of the vinyl chloride monomer in the initial reaction mixture comprising a vinyl acetate monomer, a polymerization initiator, and a cellulose-based suspending agent. Including 50 parts by weight and starting the polymerization reaction at 40 to 70 ℃, and b) 50 to 100 parts by weight of the vinyl chloride monomer continuously added to the suspension polymerization comprising a vinyl chloride-vinylacetate air It relates to a method for producing the coalescence.

According to the present invention, the reaction time can be shortened by the optimization condition of continuously introducing the vinyl chloride monomer, and the content of vinyl acetate can be easily controlled, the content of vinyl acetate is high, the viscosity is low, and the bulk density is high. ) Has high properties, low processing temperature and excellent workability, such as flow chart, adhesive strength during processing has the effect of providing a vinyl chloride copolymer suitable for the production of vinyl composite tiles.

Vinyl composite tile, vinyl chloride-vinylacetate copolymer, vinyl acetate content, suspension polymerization, volume specific gravity, suspending agent, chain transfer agent, monomer injection

Description

Method for producing vinyl chloride-vinylacetate copolymer {METHOD FOR PREPARING POLYVINYL-VINYLACETATE COPOLYMER}

The present invention relates to a method for preparing a vinyl chloride-vinylacetate copolymer, and more particularly, the reaction time can be shortened by optimization conditions for continuously adding a vinyl chloride monomer, and the content of vinyl acetate can be easily controlled. Vinyl chloride-vinylacetate, which is suitable for the production of vinyl composite tiles due to its high content of vinyl acetate, low viscosity and high bulk density, low processing temperature and excellent workability such as flow chart and adhesion during processing. It relates to a method for producing a copolymer.

Vinyl chloride-based resin is the most widely used universal resin in the world as a living and industrial materials can be prepared by polymerizing vinyl chloride monomer alone, and can be produced by copolymerizing with various monomers at the same time. Such vinyl chloride-based resins have been widely used for various applications for a long time, and many attempts have been made to improve physical properties.

Vinyl chloride-based copolymers prepared by copolymerizing vinyl chloride monomers with various monomers have the effect of improving the thermoplasticity or fluidity of the polymer after processing and improving solubility. In general, vinyl chloride copolymers have been used as a means to reduce the difficulty of processing conditions required to process the desired final product.

Among these vinyl chloride copolymers, vinyl chloride-vinylacetate copolymers prepared by copolymerizing vinyl chloride monomers and vinyl acetate monomers are known to be the most important products to date. Although the use of the vinyl chloride-vinylacetate copolymer is largely consistent with that of polyvinyl chloride, its use is often determined by the price because vinyl acetate is almost twice as expensive as vinyl chloride.

However, even if the amount of copolymerized vinyl acetate is a small amount, the range of processing temperature is extended and the flow and gloss are significantly improved during processing, and thus, polypropylene is replaced with a copolymer instead of an expensive plasticizer.

Polyvinyl chloride and vinyl chloride-based copolymers are widely used in the crimping process, such as vinyl flooring materials, laminates of vinyl and fibers used for furniture, wallpaper, car seat cover, as well as home interior wallpaper, curtains, and floor mats. It is used for a purpose.

In general, the vinyl chloride-vinylacetate copolymer has a vinyl acetate content of about 5 to 10%, and as the content of the bound vinyl acetate increases, the initial colorability, processability, and moldability are excellent. It is suitable for application to the required vinyl composite tile.

U.S. Patent No. 3,172,877 discloses a process for preparing such vinyl chloride copolymers. However, the conventional suspension polymerization method has a problem that it is difficult to prepare a vinyl chloride-based copolymer having a low viscosity and high bulk density. Since each monomer used in the preparation of the vinyl chloride-based copolymer has a different reactivity ratio, when prepared by the conventional suspension polymerization method, the content of vinyl acetate bound to the vinyl chloride-based copolymer is lowered, and the vinyl to be bonded. When a large amount of vinyl acetate is initially added to increase the amount of acetate, the amount of vinyl acetate remaining in the vinyl chloride copolymer increases, and the colloid becomes unstable, resulting in a decrease in particle stability. There is a problem that this is lowered.

Therefore, in preparing the vinyl chloride-vinylacetate copolymer, the different reactivity of each monomer must be taken into account. Specifically, since vinyl chloride monomer is more reactive than vinyl acetate, it is necessary to maintain the vinyl chloride monomer and vinyl acetate monomer in a constant ratio at the beginning of the polymerization, and supplement the amount of vinyl chloride monomer consumed during the reaction to compensate for the reaction in the reaction system. The ratio must be kept constant.

In order to solve the problems of the prior art as described above, the reaction time can be shortened by the optimization conditions of continuously introducing the vinyl chloride-based monomer, the content of vinyl acetate can be easily controlled, the content of vinyl acetate is high, and the viscosity is high. The purpose of the present invention is to provide a method for producing a vinyl chloride-vinylacetate copolymer suitable for the production of a vinyl composite tile because of its low and bulk density characteristics, and its low processing temperature and excellent workability such as flow chart and adhesive strength during processing. It is done.

The above and other objects of the present invention can be achieved by the present invention described below.

In order to achieve the above object, the present invention is a) to the initial reaction mixture comprising a vinyl acetate monomer, a polymerization initiator, and a cellulose-based suspending agent up to 50 parts by weight of 100 parts by weight of vinyl chloride monomer and at 40 to 70 ℃ It provides a method for producing a vinyl chloride-vinylacetate copolymer comprising the step of starting the polymerization reaction, and b) suspending polymerization by continuously adding 50 to 100 parts by weight of the vinyl chloride monomer.

Hereinafter, the present invention will be described in detail.

The inventors of the present invention, while studying to solve the problems of the prior art, using a polymerization initiator, a cellulose-based suspending agent and a chain transfer agent, when the vinyl chloride monomer is continuously added during suspension polymerization, vinyl acetate It was confirmed that the content of the vinyl chloride-vinylacetate copolymer having a high content of 5 to 20% by weight, and completed the present invention based on this.

The method for producing a vinyl chloride-vinylacetate copolymer of the present invention is characterized by controlling the content of vinyl acetate in the polymerization reactant to 5 to 20% by weight by continuously adding a vinyl chloride monomer and suspending polymerization after the start of the polymerization reaction. . That is, in order to manufacture the vinyl chloride-vinylacetate copolymer, a predetermined amount of vinyl chloride monomer is added before the reaction of the vinyl acetate monomer is started, based on the reactivity ratio of the vinyl chloride monomer and the vinyl acetate, and the ratio of the vinyl chloride monomer and the vinyl acetate. In order to maintain the content of the vinyl acetate monomer at the beginning and end of the polymerization reaction by the constant rate of the vinyl chloride monomer is continuously added throughout the reaction time.

The method for preparing the vinyl chloride-vinylacetate copolymer may include (a) at most 50 parts by weight, preferably at most, up to 100 parts by weight of the vinyl chloride monomer in the initial reaction mixture comprising the vinyl acetate monomer, the polymerization initiator, and the cellulose suspending agent. Adding 30 parts by weight, initiating the polymerization at a reaction temperature of 40-70 ° C., and (b) 50-100 parts by weight of the remaining vinyl chloride monomer, preferably 70-100 parts by weight, continuously throughout the reaction time. It is a method comprising the step of suspending polymerization.

The initial reaction mixture includes a vinyl acetate monomer, a polymerization initiator, and a cellulose suspending agent. In addition to the above components, the initial reaction mixture may include deionized water, an antifoaming agent or a buffer generally used in suspension polymerization.

The vinyl acetate monomer may be used in 5 to 20 parts by weight based on 100 parts by weight of the vinyl chloride monomer.

The polymerization initiator may be a water-soluble initiator such as potassium persulfate, ammonium persulfate, hydrogen peroxide, benzoyl peroxide, lauryl peroxide, acetyl cyclohexanol peroxide, 2,4,4-trimethylpentyl-2-peroxy neo Decanoate, α-cumyl peroxy neodecanoate, di-butylperoxy dicarbonate, cumene hydroperoxide, t-butylhydroxy peroxide, bis (2-ethylhexyl) peroxy dicarbonate, t-butyl Organic peroxide initiators such as peroxy pivalate or azo initiators such as azobisisobutyronitrile and azobis-2,4-dimethylvaleronitrile.

The polymerization initiator may be used in an amount of 0.01 to 0.04 parts by weight based on 100 parts by weight of the vinyl chloride monomer. In the case of using the content, it is possible to improve the productivity by controlling the reaction time and to control the calorific value, there is also an excellent effect on the price without deterioration of physical properties due to the residual polymerization initiator.

The cellulose-based suspending agent is a dispersant added to improve the suspension stability to efficiently perform the polymerization reaction, partially gummed VOH resin, hydroxide cellulose, gelatin, acrylate or acrylate copolymer, polyethylene glycol, polyvinylpyrroly Pigment or copolymerized resins of maleic anhydride and styrene and the like can be used alone or in combination of two or more. It is preferable to use hydroxide cellulose or gelatin having a viscosity of 1000 cP in a 2% by weight aqueous solution.

The cellulose suspending agent may be used in an amount of 0.1 to 0.3 parts by weight based on 100 parts by weight of the vinyl chloride monomer. When used in the above content is excellent in the initial polymerization dispersion stability, small particles and abnormal particles are not produced, there is an effect that the volume specific gravity increases.

50 to 100 parts by weight of the vinyl chloride monomer may be continuously added over the entire reaction time at an input rate of 10 to 25 parts by weight per hour.

When continuously added as described above has the effect of adjusting the composition of the final vinyl chloride copolymer by controlling the rate of the input of the vinyl chloride monomer.

The initial reaction mixture may further include a chain transfer agent.

As the chain transfer agent, ethylhexyl mercapto acetate, propionaldehyde, 2-mercaptoethanol, or butylaldehyde may be used alone or in combination of two or more thereof. , Preferably mermertoethanol (2-mercaptoethanol).

The chain transfer agent may be used in an amount of 0.03 to 0.06 parts by weight based on 100 parts by weight of the vinyl chloride monomer. When used in the above content, the molecular weight is reduced, and the scale of the reactor wall is greatly reduced as well as the volume specific gravity is further increased.

In the method for preparing the vinyl chloride-vinylacetate copolymer, a vacuum is applied to the reactor to remove oxygen, a deionized water, a buffer, a vinyl acetate monomer, a polymerization initiator, and a suspending agent are added all at once, and a maximum of 100 parts by weight of the vinyl chloride monomer is used. 50 parts by weight was added to initiate the polymerization reaction at a reaction temperature of 40 to 70 ℃, the remaining 50 to 100 parts by weight of the vinyl chloride monomer was continuously added at a reaction rate of 10 to 25 parts by weight per hour and reacted, unreacted residual vinyl chloride After recovering the monomer, a vinyl chloride-vinylacetate copolymer prepared is separated, dehydrated and dried.

The vinyl chloride-vinylacetate copolymer prepared by the above method is a spherical particle having an average particle diameter of 100 to 200 µm and a bulk density of 0.6 to 0.8 g / cc, preferably 0.7 to 0.8 g /. cc, the specific viscosity is 1.6 to 1.65, the content of vinyl acetate is preferably 5 to 20% by weight. The vinyl chloride-vinylacetate copolymer having the above characteristics has good transparency at the time of dissolution, low processing temperature, excellent flowability and adhesion during processing, excellent initial coloring property and moldability, and thus, for the production of vinyl composite tiles. There is a suitable effect.

Hereinafter, preferred examples are provided to aid the understanding of the present invention, but the following examples are merely for exemplifying the present invention, and it will be apparent to those skilled in the art that various changes and modifications can be made within the scope and spirit of the present invention. It is natural that such variations and modifications fall within the scope of the appended claims.

[Example]

Example 1

In a 1000 L high-pressure reactor with deionized water, 0.25 parts by weight of hydroxypropyl methyl cellulose, 15 parts by weight of vinyl acetate comonomer, 0.049 parts by weight of silox as defoamer, and polymerization initiator, based on 100 parts by weight of vinyl chloride monomer. 0.02 part by weight of bis (2-ethylhexyl) peroxy dicarbonate, 0.034 part by weight of t-butylperoxy pivalate, 0.02 part by weight of NaHCO ₃ , 0.049 part by weight of mercantoethanol as a chain transfer agent, followed by vacuum and stirring 0 weight part of vinyl chloride monomers were added together, and it heated up at 63 degreeC and started the polymerization reaction.

100 parts by weight of vinyl chloride monomer was continuously added to the reactor at a feed rate of 25 parts by weight over 4 hours, and then the reaction was performed until the reactor pressure drop was reduced to 3 kgf / cm ² .

After the reaction was completed, the unreacted vinyl chloride monomer and vinyl acetate comonomer were recovered and removed, and the reactor was cooled, dehydrated, and dried to prepare a vinyl chloride-vinylacetate copolymer.

Example 2

After the polymerization reaction was started by adding 20 parts by weight of the vinyl chloride monomer in Example 1, the same as in Example 1 except that 80 parts by weight of the remaining vinyl chloride monomer was added over 4 hours at a rate of 20 parts by weight per hour. It was carried out by the method.

Example 3

After the polymerization reaction was started by adding 30 parts by weight of the vinyl chloride monomer in Example 1, 70 parts by weight of the remaining vinyl chloride monomer was added over 4 hours at an input rate of 17.5 parts by weight per hour. It was carried out by the method.

Example 4

After the polymerization reaction was started by adding 40 parts by weight of the vinyl chloride monomer in Example 1, the same as in Example 1 except that the remaining 60 parts by weight of vinyl chloride monomer was added over 4 hours at an input rate of 15 parts by weight per hour. It was carried out by the method.

Example 5

After initiating the polymerization reaction by adding 50 parts by weight of the vinyl chloride monomer in Example 1, the same as in Example 1 except that 50 parts by weight of the remaining vinyl chloride monomer was added over 4 hours at an input rate of 12.5 parts by weight per hour. It was carried out by the method.

Comparative Example 1

In Example 1, the polymerization was carried out in the same manner as in Example 1, except that 100 parts by weight of the vinyl chloride monomer was polymerized in a batch manner at the beginning of the polymerization reaction.

Comparative Example 2

After the polymerization reaction was initiated by adding 33.3 parts by weight of vinyl chloride monomer at the beginning of the polymerization reaction in Example 1, two steps of 33.3 parts by weight of the remaining vinyl chloride monomer at 4.5 kgf / cm ² and 4.5 kgf / cm ² respectively. The same process as in Example 1 was carried out except that divided into 2 parts.

[Test Example]

The physical properties of the vinyl chloride-vinylacetate copolymers prepared in Examples 1 to 5 and Comparative Examples 1 to 2 were measured by the following method, and the results are shown in Table 1 below.

A) Average particle diameter-measured according to ASTM D1705.

B) Volume specific gravity-measured according to ASTM D1895-89.

C) Vinyl Acetate (VAc) content-A sample specimen was prepared and measured by IR and calculated as CH, -CH ₂ peak.

D) specific viscosity (η _sp ) -measured according to ASTM D1243-79.

ㅁ) Adhesion-measured according to ASTM D6392.

◎: The level with the highest peel strength value compared with the specimen of Comparative Example 1

(Circle): The level with which the maximum peel strength value is equal compared with the test piece of the comparative example 1

X: The level with which the maximum peel strength value is low compared with the test piece of the comparative example 1

Viii) Workability-measured according to ASTM D2538-95.

◎: High level of maximum torque compared to the specimen of Comparative Example 1

(Circle): The level with which the maximum torque value is equal compared with the test piece of the comparative example 1.

X: The level with a lower maximum torque value compared with the specimen of Comparative Example 1

division Example
One Example
2 Example
3 Example
4 Example
5 Comparative Example 1 Comparative example
2 Average particle size (㎛) 198 195 179 156 147 205 176 Particle size distribution 1.4 1.6 1.7 1.9 2.0 1.4 1.8 Content (%) of particles with an average particle diameter of 200 µm or more 0.0 0.0 0.1 0.0 0.8 2.1 0.3 Volume specific gravity (g / cc) 0.79 0.78 0.76 0.68 0.61 0.53 0.77 Vinyl acetate content (%) 13.5 13.9 14.8 12.6 12.5 10.1 12.2 Reaction time 10.9 10.8 10.5 10.1 9.8 11.1 12.3 Specific viscosity (η _sp ) 1.61 1.63 1.62 1.61 1.60 1.71 1.63 Adhesive ○ ○ ◎ ◎ ◎ - ○ Machinability ◎ ◎ ◎ ○ ○ - ○

As shown in Table 1, the chloride of Examples 1 to 5 prepared by initiating the polymerization reaction by adding up to 50 parts by weight of the vinyl chloride monomer at the beginning of the reaction according to the present invention, and continuously adding the remaining vinyl chloride monomer Vinyl-vinylacetate copolymer was found to have a high vinyl acetate content, low viscosity, high volume specific gravity, excellent adhesion and processability. Among them, in the case of Examples 1 to 3 in which the vinyl chloride monomer was added at a maximum of 30 parts by weight at the beginning of the reaction to initiate the polymerization reaction, the volume specific gravity was 0.7 g / cc or more, and the vinyl acetate content was high, particularly vinyl chloride monomer. In the case of Example 3, which was added at 30 parts by weight at the beginning of the reaction to initiate the polymerization reaction, it was confirmed that the adhesiveness and workability were also excellent. Therefore, it was more preferable to start the polymerization reaction by adding 30 parts by weight of vinyl chloride monomer at the beginning of the reaction.

On the other hand, Comparative Example 1 prepared by batch-adding a vinyl chloride monomer at the beginning of the reaction in a conventional batch method, the reaction time was longer, the content of particles having an average particle diameter of 200 μm or more was slightly increased, and the content of vinyl acetate. It was confirmed that this is low, the viscosity is high, and the volume specific gravity is also low. In addition, Comparative Example 2 prepared by stepwise addition of a vinyl chloride monomer was added stepwise by adding a low temperature vinyl chloride monomer stepwise, the temperature in the reactor is instantaneously reduced, so it takes time to adjust to the appropriate reaction temperature reaction The time was considerably longer, and it was confirmed that the adhesiveness and processability were also slightly decreased.

As described above, according to the present invention, the reaction time can be shortened by the optimization condition of continuously introducing the vinyl chloride monomer, the content of vinyl acetate can be easily controlled, the content of vinyl acetate is high, and the viscosity is low. Since the bulk density is high, the processing temperature is low and the workability such as flow chart, adhesive strength and the like during processing is excellent, thereby providing a vinyl chloride copolymer suitable for producing a vinyl composite tile.

Claims (8)

a) adding up to 50 parts by weight of 100 parts by weight of the vinyl chloride monomer to an initial reaction mixture comprising a vinyl acetate monomer, a polymerization initiator, and a cellulose suspending agent and initiating the polymerization at 40 to 70 ° C .; and b) 50 to 100 parts by weight of the vinyl chloride monomer at 10 to 25 parts by weight of the injection rate by the step of suspension polymerization; In the initial reaction mixture of step a), at least one chain transfer agent selected from the group consisting of ethylhexyl mercetoacetate, propionaldehyde, mercetoethanol, and butyl aldehyde is 0.03 to 0.06 parts by weight based on 100 parts by weight of the vinyl chloride monomer. Including more, The produced vinyl chloride-vinylacetate copolymer is used as a resin for vinyl composite tiles Method for preparing vinyl chloride-vinylacetate copolymer. The method of claim 1, In step a) up to 30 parts by weight of the vinyl chloride monomer 100 parts by weight, and in step b) 70 to 100 parts by weight of the vinyl chloride monomer, characterized in that Method for preparing vinyl chloride-vinylacetate copolymer. delete The method of claim 1, The vinyl acetate monomer is used in 5 to 20 parts by weight based on 100 parts by weight of vinyl chloride monomer Method for preparing vinyl chloride-vinylacetate copolymer. The method of claim 1, The polymerization initiator is used in an amount of 0.01 to 0.04 parts by weight based on 100 parts by weight of the vinyl chloride monomer. Method for preparing vinyl chloride-vinylacetate copolymer. The method of claim 1, The cellulose-based suspending agent is at least one selected from the group consisting of partially saponified VOH resin, cellulose hydroxide, gelatin, acrylate or acrylate copolymer, polyethylene glycol, polyvinyl pyrrolidone, and maleic anhydride and styrene copolymer resin. And 0.1 to 0.3 parts by weight based on 100 parts by weight of the vinyl chloride monomer. Method for preparing vinyl chloride-vinylacetate copolymer. delete The method of claim 1, The vinyl chloride-vinylacetate copolymerization is characterized in that the content of vinyl acetate is 5 to 20% by weight. Method for preparing vinyl chloride-vinylacetate copolymer.