WO2017047987A1 - Vinyl chloride-vinyl acetate copolymer, and preparation method therefor - Google Patents

Abstract

The present invention relates to a vinyl chloride-vinyl acetate copolymer exhibiting excellent tensile strength even at low processing temperatures, and a preparation method therefor. According to the present invention, the copolymer comprises a vinyl acetate-derived unit in a specific ratio, and has a polydispersity index of a specific range, for example, a polydispersity index of 2.1-2.4, in the range of a degree of polymerization of 1,200-1,300, so as to exhibit excellent tensile strength even in low-temperature processing. Therefore, according to the present invention, the vinyl chloride-vinyl acetate copolymer and a preparation method therefor can be readily applied to an industry requiring the same, particularly, the automotive industry or the polyvinyl chloride resin industry.

Description

Vinyl chloride-vinylacetate copolymer and preparation method thereof

[Citations with Related Applications]

This application claims the benefit of priority based on Korean Patent Application No. 10-2015-0129709 filed on September 14, 2015 and Korean Patent Application No. 10-2016-0114396 filed on September 6, 2016, and all contents disclosed in the literature of the Korean patent application. Is included as part of this specification.

[Technical Field]

The present invention relates to a vinyl chloride-vinylacetate copolymer capable of expressing excellent tensile strength even at low temperature processing and a method of manufacturing the same.

Vinyl chloride-based resins are the most widely used general-purpose resins worldwide for living and industrial materials, and are known to be prepared by polymerizing vinyl chloride monomers alone and copolymerizing with various monomers. 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 and various monomers have an 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 the vinyl chloride polymer (PVC), 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 expanded and the flow, gloss, adhesiveness, mechanical strength, etc. are changed during processing, so that various applications are considered in consideration of the above characteristics.

These vinyl chloride-vinylacetate copolymers are used in a wide variety of applications such as vinyl flooring materials, vinyl and fiber repellents used in furniture, wallpaper, decorative wallpaper for homes, curtains, floor mats and sealants or automotive underbody coatings. Is being used.

On the other hand, sealants or automotive underbody coatings are manufactured at lower processing temperatures than existing processing temperatures due to productivity and environmental issues. However, a product processed at a low processing temperature has a disadvantage in that the tensile strength is relatively lower than that of a product processed at a relatively high processing temperature.

Therefore, in order to easily apply the vinyl chloride-vinylacetate copolymer to the industry, particularly in the sealant or automotive underbody coating materials industry, vinyl chloride-vinylacetate air can exhibit excellent tensile strength even when processed under low processing temperature conditions. The development of coalition is needed.

The present invention has been made to solve the problems of the prior art, and an object of the present invention is to provide a vinyl chloride-vinylacetate copolymer capable of expressing excellent tensile strength even at low temperature processing.

Another object of the present invention is to provide a method for preparing the vinyl chloride-vinylacetate copolymer.

In order to solve the above problems, the present invention provides a polyvinyl chloride-vinylacetate air containing polydispersity index (PDI) of 2.1 to 2.4 in the range of polymerization degree 1200 to 1300, and containing 4% to 7% by weight of vinyl acetate derived units. Provide coalescence.

In addition, the present invention is a mixture of 50% to 80% by weight of the vinyl chloride monomer and 100% by weight of vinyl acetate monomer 100 parts by weight of vinyl acetate monomer in a total amount of 100% by weight of vinyl chloride monomer mixed with a homogenized and then polymerized Initiating the reaction (step 1); And 20 to 50% by weight of the vinyl chloride monomer after the start of the polymerization reaction to provide a method for producing the vinyl chloride-vinylacetate copolymer comprising the step of participating in the polymerization reaction (step 2).

The vinyl chloride-vinylacetate copolymer according to the present invention is excellent in low temperature processing by having a vinylacetate-derived unit of a specific content range and a polydispersity index of a specific range, such as 2.1 to 2.4, in a polymerization degree of 1200 to 1300. Tensile strength can be expressed.

In addition, in the method for producing a vinyl chloride-vinylacetate copolymer according to the present invention, a part of the total amount of the vinyl chloride monomer used in the polymerization is added to the vinyl acetate before starting the polymerization reaction without the entire amount of the vinyl chloride monomer being added before the polymerization reaction starts. After the polymerization reaction is started by adding together with the monomer, the remaining part is added at once at a specific time point, such as 1/3 or more of the total reaction time, to participate in the polymerization reaction to easily form a vinyl chloride-vinylacetate copolymer. It may be possible to have a polydispersity index in the above-described range.

In addition, the processed article prepared by low-temperature processing the plastisol containing the vinyl chloride-vinylacetate copolymer according to the present invention may have excellent tensile strength.

Therefore, the vinyl chloride-vinylacetate copolymer and its preparation method according to the present invention can be usefully applied to industries in need thereof, in particular, to the automobile industry and the polyvinyl chloride resin industry.

Hereinafter, the present invention will be described in more detail to aid in understanding the present invention.

The terms or words used in this specification and claims are not to be construed as limiting in their usual or dictionary meanings, and the inventors may appropriately define the concept of terms in order to best describe their invention. It should be interpreted as meaning and concept corresponding to the technical idea of the present invention based on the principle that the present invention.

The present invention provides a vinyl chloride-vinylacetate copolymer capable of expressing excellent tensile strength properties even at low temperature processing.

Vinyl chloride-vinylacetate copolymer has excellent properties such as flow and gloss during processing and good physical properties, so it can be widely used as sealant or underbody coating material in automobile industry as well as wallpaper, curtain and floor mat for home interior. It is used in the field. In general, the vinyl chloride-vinylacetate copolymer is mixed with various additives such as colorants and heat stabilizers to form a processing composition, and various fields as described above through different processing processes depending on the purpose such as extrusion process, calendar process, injection process, and paste processing. It is manufactured and used as a product.

For example, in the case of sealant or automotive underbody coating material, a vinyl chloride-vinylacetate copolymer plastisol is used to manufacture a product through a process such as dipping, spraying, and coating. , The processing is carried out under temperature conditions of 160 ℃ to 180 ℃ or more. On the other hand, in recent years, as the interest in productivity and environment of the automobile industry is heightened, methods for improving productivity by increasing ease of processing and at the same time, manufacturing products more environmentally friendly are being implemented. As an example of this, products are manufactured by processing under relatively low processing temperature conditions, and methods for gradually lowering processing temperatures are being considered. However, when processing at a low processing temperature there is a problem that the tensile strength of the product is reduced, the decrease in the tensile strength is shown to be larger as the processing temperature is lowered. Therefore, in order to easily apply the vinyl chloride-vinylacetate copolymer to changing industrial environments (eg, productivity and environmental problems), the vinyl chloride-vinylacetate copolymer can be obtained to obtain a product having excellent tensile strength even at low temperature processing. Development is needed.

Accordingly, the present invention provides a vinyl chloride-vinylacetate copolymer capable of expressing excellent tensile strength properties even at low temperature processing.

The vinyl chloride-vinylacetate copolymer according to an embodiment of the present invention has a polydispersity index (PDI) of 2.1 to 2.4 in a polymerization degree of 1200 to 1300, and includes 4 to 7 wt% of vinyl acetate derived units. It is characterized by.

Specifically, the vinyl chloride-vinylacetate copolymer may have a polydispersity index (PDI) of more than 2.1 and less than 2.3 in a polymerization degree of 1200 to 1300, and include 5 wt% to 6 wt% of vinyl acetate derived units. Can be.

If the vinyl chloride-vinylacetate copolymer contains a vinyl acetate derived unit outside the content of 4% by weight to 7% by weight, the low-temperature tensile strength of the processed product manufactured by low-temperature processing thereof is significantly reduced. May occur. Here, the low temperature tensile strength is as described later.

The term "derived unit" in the present invention may be a structure or component generated by any substance or may refer to any such substance itself. For example, the vinyl acetate derived unit may be a structure or component derived from vinyl acetate or may represent a vinyl acetate itself structure.

In addition, the vinyl chloride-vinylacetate copolymer according to an embodiment of the present invention is characterized in that the weight average molecular weight (Mw) is 160,000 g / mol to 165,000 g / mol.

The term "degree of polymerization" in the present invention refers to the number of repeated units (units or monomers) that make up the polymer.

In the present invention, the term "polydispersity index" refers to the molecular weight distribution of the polymer and is a value representing the ratio (Mw / Mn) of the weight average molecular weight (Mw) and the number average molecular weight (Mn).

The degree of polymerization is a value measured according to JIS K6720-2. The polydispersity index is a weight average molecular weight (Mw) after measuring the weight average molecular weight (Mw) and the number average molecular weight (Mn), the number average molecular weight (Mn) It is obtained by dividing by. In this case, the weight average molecular weight (Mw) and the number average molecular weight (Mn) is 0.02 g of the vinyl chloride-vinylacetate in 20 ml of tetrahydrofuran (tetrahydrofuran) and stirred for 24 hours to completely melt and then gel permeation chromatography (GPC) Standard samples (S-1.3, S-2.8, S-6.8, S-20, S-51, S-126, S-282, S-791, S), measured using an instrument (Waters 2414, Waters, Inc.) -1640 and S-258, Showa Denko kk) are used to draw the calibration curve and convert it.

The vinyl chloride-vinylacetate copolymer according to an embodiment of the present invention has a polydispersity index of 2.1 to 2.4 in a polymerization degree of 1200 to 1300 as described above, and includes a vinylacetate-derived unit at a specific ratio during low temperature processing. Also excellent tensile strength can be expressed. Accordingly, the low-temperature tensile strength of the processed product manufactured by using the vinyl chloride-vinylacetate copolymer plastisol at low temperature may be excellent.

Specifically, the vinyl chloride-vinylacetate copolymer according to an embodiment of the present invention may have a tensile strength of 10 MPa to 14 MPa, an elongation (%) may be 600% to 1,100%, and transparency (%) May be from 80% to 92%.

In this case, the tensile strength, elongation and transparency are respectively measured by using the specimen after heat-treating the copolymer at 130 ℃ 30 minutes to prepare a specimen of width 6.25 mm and thickness 1.5 mm.

Specifically, the specimen is a plastisol prepared by mixing 60 g of a plasticizer (dioctylphthalate) and 2 g of a stabilizer (SONGSTAB ^™ BZ-119, Songwon Industry) to 100 g of vinyl chloride-vinylacetate copolymer. After coating to a thickness of mm and left for 30 minutes in an oven at a temperature of 130 ℃, it may represent a processed product prepared by low-temperature processing using the vinyl chloride-vinylacetate copolymer. Here, since the remaining materials except the vinyl chloride-vinylacetate copolymer, such as the plasticizer and the stabilizer, are used as additives for ease of processing, the tensile strength, elongation and transparency of the specimen may be obtained from the vinyl chloride-vinylacetate copolymer itself. It may be a characteristic that is expressed.

In addition, the tensile strength and elongation is a value measured using a tensile strength meter (model name: Zwick Co., Ltd.) in accordance with ASTM D638 using the specimen, the transparency is Haze-gard plus (BYK) using the specimen It is measured by the company.

The present invention also provides a method for producing the vinyl chloride-vinylacetate copolymer.

The preparation method according to an embodiment of the present invention is from 5.5 to 10 parts by weight of vinyl acetate monomer with respect to 50 to 80% by weight of vinyl chloride monomer and 100 parts by weight of the vinyl chloride monomer in 100% by weight of the total amount of vinyl chloride monomer. Mixing the parts by weight, homogenizing and initiating a polymerization reaction (step 1); And incorporating 20 wt% to 50 wt% of the vinyl chloride monomer after the polymerization reaction starts to participate in the polymerization reaction (step 2).

The polymerization may be an emulsion polymerization, specifically, may be a microemulsion polymerization.

Step 1 is a step of starting the polymerization reaction using a part of the vinyl chloride monomer and vinyl acetate monomer, 50% to 80% by weight of the vinyl chloride monomer and 100% of the vinyl chloride monomer used in the polymerization. The total amount of the monomers may be performed by mixing and homogenizing 5.5 to 10 parts by weight of vinyl acetate monomer with respect to 100 parts by weight of the monomer and initiating a polymerization reaction. At this time, the polymerization may be performed under a temperature range of 30 ℃ to 70 ℃.

Specifically, step 1 may be carried out by adding a polymerization initiator and a vinyl chloride monomer and a vinyl acetate monomer in the above-described contents into a reactor filled with an emulsifier, mixing and homogenizing, and initiating a polymerization reaction.

The reactor filled with the emulsifier may represent a reactor containing a mixed solution containing an emulsifier, and the mixed solution may further include additives such as polymerized water and an emulsifying aid in addition to the emulsifier.

The emulsifier is not particularly limited, but may be used in an amount of 0.1 parts by weight to 5 parts by weight based on 100 parts by weight of the total amount of vinyl chloride monomer used in the polymerization. In addition, the emulsifier is selected from the group consisting of linear alkylbenzene sulfonates, sodium lauryl sulfate, lauryl benzene sulfonic acid, alpha-olefin sulfonates, sodium lauryl epoxidized sulfate, sodium octadecyl sulfate and sodium lauryl ether sulfate. It may be one or more, but is not limited thereto.

The emulsifying adjuvant is not particularly limited, but for example, alcohols such as lauryl alcohol, cetyl alcohol, mystic alcohol, stearyl alcohol or higher fatty acids such as lauryl acid, myristic acid, palmitic acid and stearic acid may be used. have.

In addition, the mixed solution may further comprise a reaction inhibitor, if necessary, the reaction inhibitor is hydroquinone, butylated hydroxy toluene, monomethyl ether hydroquinone, quaternary butyl catechol, diphenyl amine, triiso It may be one or more of propanol amine and triethanol amine, but is not limited thereto.

The polymerization initiator is not particularly limited, but may be used in an amount of 0.01 parts by weight to 2 parts by weight based on 100 parts by weight of the total amount of vinyl chloride monomer used in the polymerization. In addition, the polymerization initiator may be an oil-soluble polymerization initiator, specifically, cumene hydroperoxide, diisopropyl benzene hydroperoxide, azobis isobutyronitrile, tertiary butyl hydroperoxide, paramentane hydroperoxide, It may be one or more selected from the group consisting of benzoyl peroxide and di-2-ethylhexyl peroxy dicarbonate, but is not limited thereto.

The homogenization is not particularly limited, but for example, the high pressure homogenizer is subjected to a total pressure of 800 psi to 1400 psi at a temperature of 40 ° C. or lower, specifically 5 ° C. to 15 ° C., at a front end and a rear end of 1: 9 to 9: Driving to be dispensed at a ratio of 1 may be performed for 1 to 3 hours.

Step 2 is a step for preparing the vinyl chloride-vinylacetate copolymer by adding the remaining vinyl chloride monomer to the polymerization reaction, the remaining 20 to 50% by weight of the total amount of the vinyl chloride monomer used in the polymerization 100% by weight The vinyl chloride monomer of may be added to the reactor of step 1 and participated in the polymerization reaction. In this case, the vinyl chloride monomer introduced before the polymerization reaction and the vinyl chloride monomer introduced after the polymerization reaction may have a weight ratio of 4: 1 to 1: 1.

20 wt% to 50 wt% of the vinyl chloride monomer added in Step 2, that is, the vinyl chloride monomer added after the start of the polymerization reaction may be added at one time in a batch, divided into several time points, or divided into any one time point. It may be to continuously input in a uniform amount for a predetermined time before the completion of the polymerization.

Specifically, the vinyl chloride monomer to be added after the polymerization reaction is 20 to 50% by weight at the time of 1/3 or more of the total reaction time, or 20 from the time of more than 1/3 of the total reaction time Weight% to 50% by weight may be to continuously input at an injection rate of 3% to 17% by weight per hour. More specifically, at the time of 1/2 or more, the above-mentioned amount may be collectively added or continuously.

In this case, the total reaction time represents the time from the time when the reactor internal temperature reaches the polymerization temperature to the time when the polymerization is terminated (for example, when the internal pressure of the reactor decreases to 3.5 kg / cm ² ).

According to an exemplary embodiment of the present invention, a vinyl chloride monomer and vinyl are introduced into a reaction system by adding a part of vinyl chloride monomer to initiate a polymerization reaction, and then adding or continually adding the remaining vinyl chloride monomer at a specific time after the polymerization reaction is started. By appropriately maintaining the proportion of the acetate monomer, a vinyl chloride-vinylacetate copolymer having a desired composition ratio can be easily produced.

Specifically, since the vinyl chloride monomer is more reactive than the vinyl acetate monomer, in order to easily prepare the vinyl chloride-vinylacetate copolymer, the ratio of the vinyl chloride monomer and the vinyl acetate monomer in the reactor at the beginning of the polymerization reaction and during the polymerization reaction is constant. It is necessary to maintain. If the total amount of the vinyl chloride monomer is added together with the vinyl acetate monomer before the polymerization is started, the polymerization reaction may be performed at a late stage of polymerization (eg, at the end of the polymerization). The reaction may be high. As a result, the content of the vinyl acetate-derived unit in the vinyl chloride-vinylacetate copolymer produced as a result may be lowered, or the polydispersity index of the copolymer may increase beyond the desired range.

In addition, the manufacturing method according to an embodiment of the present invention may further include one or more steps of washing, flocculating and drying after step 2.

In addition, the present invention provides a plastisol comprising the vinyl chloride-vinylacetate copolymer and a processed product manufactured using the plastisol.

Specifically, the plastisol may include 100 parts by weight of a vinyl chloride-vinylacetate copolymer and 40 parts by weight to 120 parts by weight of a plasticizer, and additives such as a dispersion diluent, a heat stabilizer, a viscosity reducing agent, and a foaming agent, as necessary. It may further include.

As used herein, the term "plastisol" refers to a mixture of a resin and a plasticizer for processing into a mold, a mold or a continuous film by heating, for example, a vinyl chloride-vinylacetate copolymer and a plasticizer are mixed. It may be one paste.

The term "plasticizer" in the present invention may refer to an organic additive material that serves to improve the molding processability at high temperature of the resin by adding to the thermoplastic resin to increase the thermoplastic.

The plasticizer and the additive are not particularly limited and may be those conventional in the art.

In addition, the processed product may be a paste processed product prepared by paste processing using a plastisol. The processed product may be produced using a plastisol containing the vinyl chloride-vinylacetate copolymer according to an embodiment of the present invention, thereby exhibiting excellent tensile strength characteristics as described above.

Hereinafter, the present invention will be described in more detail with reference to Examples and Experimental Examples. However, the following Examples and Experimental Examples are provided to illustrate the present invention, and the scope of the present invention is not limited only to these examples.

Example  One

A mixture prepared by mixing 4 kg of sodium dodecylbenzene sulfonate and 10 kg of fatty alcohol in 400 kg of deionized water was added to a reactor having an internal volume of 1 m ³ equipped with a stirrer and di- (2-ethylhexyl) peroxy 180 g of dicarbonate (75%), 300 kg of vinyl chloride monomer, and 30 kg of vinyl acetate monomer were added and vigorously stirred to mix, and then 1 to 1400 psi of the homogenizer was distributed at a ratio of 1: 1 at the front and rear ends, respectively. Homogenization was carried out. Thereafter, the reaction mixture was transferred to a reactor having a volume of 1 m ^{3 and} the temperature inside the reactor was raised to 45 ° C. to initiate the polymerization reaction. At 7 hours after the start of the polymerization reaction (50% of the total reaction time), 100 kg of vinyl chloride monomer was added to the reactor in a batch to participate in the polymerization reaction. Thereafter, when the internal pressure of the reactor was reduced to 3.5 kg / cm ² , the polymerization was terminated and the unreacted monomer was recovered and removed to obtain a vinyl chloride-vinylacetate copolymer latex. The latex was spray dried to obtain a powdered vinyl chloride-vinylacetate copolymer. The latex had a pH of 3.07, 44.03 wt% of total solids content (TSC), and an average particle diameter of 1.089 μm.

The average particle diameter of the latex was measured by using a DC24000 UHR (CPS Instruments, Inc.) weight average particle diameter at 24000 rpm.

Example  2

100 kg of vinyl chloride monomer was added to powder phase through the same method as in Example 1, except that at the time of 9 hours (about 65% of the total reaction time), not the time of 7 hours after the start of the polymerization reaction. A vinyl chloride-vinylacetate copolymer was obtained. Here, the vinyl chloride-vinylacetate copolymer latex before spray drying was pH 3.43, 44.6 wt% of total solids content (TSC), and an average particle diameter of 1.054 μm.

Example  3

100 kg of the vinyl chloride monomer was added in the same manner as in Example 1 except that it was added at 11 hours (about 80% of the total reaction time) instead of 7 hours after the start of the polymerization reaction. A vinyl chloride-vinylacetate copolymer was obtained. Here, the vinyl chloride-vinylacetate copolymer latex before spray drying was pH 3.45, total solids content (TSC) 44.18 wt%, and average particle diameter 1.051 mu m.

Example  4

160 g of di- (2-ethylhexyl) peroxy dicarbonate (75%) was used, and the vinyl chloride monomer was added at 200 kg instead of 300 kg before the polymerization reaction was started, and 11 hours after the polymerization reaction was started ( Powdered vinyl chloride-vinylacetate copolymer was obtained in the same manner as in Example 1, except that 200 kg was added at about 80% of the total reaction time. Here, the vinyl chloride-vinylacetate copolymer latex before spray drying had a pH of 3.39, a total solids content (TSC) of 44.23 wt%, and an average particle diameter of 1.043 μm.

Example  5

A mixture prepared by mixing 4 kg of sodium dodecylbenzene sulfonate and 10 kg of fatty alcohol in 400 kg of deionized water was added to a reactor having an internal volume of 1 m ³ equipped with a stirrer and di- (2-ethylhexyl) peroxy 180 g of dicarbonate (75%), 300 kg of vinyl chloride monomer, and 30 kg of vinyl acetate monomer were added and vigorously stirred to mix, and then 1 to 1400 psi of the homogenizer was distributed at a ratio of 1: 1 at the front and rear ends, respectively. Homogenization was carried out. Thereafter, the reaction mixture was transferred to a reactor having a volume of 1 m ^{3 and} the temperature inside the reactor was raised to 45 ° C. to initiate the polymerization reaction. From 7 hours after the start of the polymerization reaction (50% of the total reaction time), 100 kg of vinyl chloride monomer was uniformly added for 7 hours (approximately 15 kg / hr) to participate in the polymerization reaction. Thereafter, when the internal pressure of the reactor was reduced to 3.5 kg / cm ² , the polymerization was terminated and the unreacted monomer was recovered and removed to obtain a vinyl chloride-vinylacetate copolymer latex. The resulting latex was spray dried to obtain a powdered vinyl chloride-vinylacetate copolymer. Here, the vinyl chloride-vinylacetate copolymer latex before spray drying was pH 3.26, total solids content (TSC) 44.52 wt% and average particle diameter 1.024 μm.

Example  6

Except that 100 kg of vinyl chloride monomer was uniformly added (approximately 33 kg / hr) for 3 hours from the time of 11 hours after the start of the polymerization reaction (about 80% of the total reaction time) and Example 5 and Through the same method, a powdered vinyl chloride-vinylacetate copolymer was obtained. Here, the vinyl chloride-vinylacetate copolymer latex before spray drying had a pH of 3.39, a total solids content (TSC) of 44.22 wt%, and an average particle diameter of 1.017 μm.

Example  7

Before starting the polymerization reaction, vinyl chloride monomer was added at 200 kg instead of 300 kg, and 100 kg of vinyl chloride monomer was uniformly added continuously for 3 hours from the time 11 hours after the start of the polymerization reaction (about 80% of the total reaction time). Powdered vinyl chloride-vinylacetate copolymer was obtained in the same manner as in Example 5 except that (in about 67 kg / hr). Here, the vinyl chloride-vinylacetate copolymer latex before spray drying was pH 3.43, total solids content (TSC) 44.33 wt%, and average particle diameter 0.995 μm.

Example  8

Powdered vinyl chloride-vinylacetate copolymer was obtained in the same manner as in Example 1, except that vinyl acetate monomer was used at 23 kg instead of 30 kg. Here, the vinyl chloride-vinylacetate copolymer latex before spray drying had a pH of 3.41, a total solids content (TSC) of 44.17 wt%, and an average particle diameter of 1.105 mu m.

Example  9

Powdered vinyl chloride-vinylacetate copolymer was obtained in the same manner as in Example 1, except that vinyl acetate monomer was used at 40 kg instead of 30 kg. Here, the vinyl chloride-vinylacetate copolymer latex before spray drying had a pH of 3.19, a total solids content (TSC) of 44.04 wt%, and an average particle diameter of 1.074 μm.

Example  10

Example 1 except that vinyl chloride monomer was added at 320 kg instead of 300 kg before the polymerization reaction and 80 kg was added at the time 7 hours after the start of the polymerization reaction (about 50% of the total reaction time). Powdered vinyl chloride-vinylacetate copolymer was obtained through the same method as described above. Here, the vinyl chloride-vinylacetate copolymer latex before spray drying was pH 3.4, total solids content (TSC) 44.32 wt%, and an average particle diameter of 1.0 mu m.

Comparative example  One

A mixture prepared by mixing 4 kg of sodium dodecylbenzene sulfonate and 10 kg of fatty alcohol in 400 kg of deionized water was added to a reactor having an internal volume of 1 m ³ equipped with a stirrer and di- (2-ethylhexyl) peroxy Add 180 g of dicarbonate (75%), 400 kg of vinyl chloride monomer, and 30 kg of vinyl acetate monomer, mix with vigorous stirring, and distribute the homogenizer total pressure 1400 psi at the front and rear ends at 1: 1 ratio. Homogenization was carried out. Thereafter, the reaction mixture was transferred to a reactor having a volume of 1 m ^{3 and} the temperature inside the reactor was raised to 45 ° C. to initiate the polymerization reaction. Thereafter, when the internal pressure of the reactor was reduced to 3.5 kg / cm ² , the polymerization was terminated and the unreacted monomer was recovered and removed to obtain a vinyl chloride-vinylacetate copolymer latex. The resulting latex was spray dried to obtain a powdered vinyl chloride-vinylacetate copolymer. Here, the vinyl chloride-vinylacetate copolymer latex before spray drying was pH 3.12, total solids content (TSC) 44.84 wt%, and average particle diameter 1.017 mu m.

Comparative example  2

Powdered vinyl chloride polymer was obtained in the same manner as in Comparative Example 1 except that vinyl chloride monomer was used at 430 kg and no vinyl acetate monomer was used. Here, the vinyl chloride polymer latex before spray drying had a pH of 3.21, a total solids content (TSC) of 44.50 wt%, and an average particle diameter of 1.091 μm.

Comparative example  3

A powdered vinyl chloride-vinylacetate copolymer was obtained in the same manner as in Comparative Example 1 except that the vinyl acetate monomer was used at 25 kg. Here, the vinyl chloride-vinylacetate copolymer latex before spray drying had a pH of 3.41, a total solid content (TSC) of 44.59 wt%, and an average particle diameter of 1.059 μm.

Comparative example  4

Powdered vinyl chloride-vinylacetate copolymer was obtained in the same manner as in Example 1 except that the vinyl acetate monomer was used at 20 kg. Here, the vinyl chloride-vinylacetate copolymer latex before spray drying had a pH of 3.35, a total solids content (TSC) of 44.37 wt%, and an average particle diameter of 1.072 μm.

Comparative example  5

Powdered vinyl chloride-vinylacetate copolymer was obtained in the same manner as in Example 1 except that the vinyl acetate monomer was used in 42 kg. Here, the vinyl chloride-vinylacetate copolymer latex before spray drying was pH 3.35, total solids content (TSC) 44.01 wt%, and average particle diameter 1.098 μm.

Comparative example  6

Powdered vinyl chloride-vinylacetate copolymer was obtained in the same manner as in Example 1 except that the vinyl acetate monomer was used in 60 kg. Here, the vinyl chloride-vinylacetate copolymer latex before spray drying had a pH of 3.32, a total solids content (TSC) of 43.87 wt%, and an average particle diameter of 1.078 μm.

Comparative example  7

Example 1 except that vinyl chloride monomer was added at 335 kg instead of 300 kg before the polymerization reaction and 65 kg was added at the time 7 hours after the start of the polymerization reaction (about 50% of the total reaction time). Powdered vinyl chloride-vinylacetate copolymer was obtained through the same method as described above. Here, the vinyl chloride-vinylacetate copolymer latex before spray drying had a pH of 3.36, a total solids content (TSC) of 44.21 wt%, and an average particle diameter of 1.094 mu m.

Comparative example  8

Example 1 except that vinyl chloride monomer was added at 135 kg instead of 300 kg before the polymerization reaction and 265 kg was added at the time 7 hours after the start of the polymerization reaction (about 50% of the total reaction time). The polymerization was carried out in the same manner as in the above, but the copolymer was not formed due to excessive aggregation.

Experimental Example  One

The physical properties of the vinyl chloride-vinylacetate copolymers prepared in Examples 1 to 10 and Comparative Examples 1 and 3 and 8 and the vinyl chloride polymers prepared in Comparative Example 2 were compared and analyzed. The results are shown in Table 1 below.

1) Vinyl acetate content (wt%)

5 mg of each copolymer and 0.5 ml of THF-d8 were added to a 1 ml vial, followed by stirring for 12 hours. Each sample was prepared, and quantitative analysis was performed using Agilent 500 MHz NMR. Was calculated by the following Equation 1 using the above quantitative analysis results.

[Equation 1]

In Equation 1, S is an integral value of methane proton peaks, M is molecular weight, VAc is vinyl acetate, and VCM is vinyl chloride monomer.

2) Determination of polymerization degree

The degree of polymerization was measured based on JIS K6720-2.

3) Weight average molecular weight (Mw), number average molecular weight (Mn) and polydispersity index (PDI)

The polydispersity index was calculated by dividing the weight average molecular weight (Mw) and the number average molecular weight (Mn) and then dividing the weight average molecular weight (Mw) by the number average molecular weight (Mn). The weight average molecular weight (Mw) and the number average molecular weight (Mn) are 0.02 g of each vinyl chloride-vinylacetate copolymer or vinyl chloride polymer in 20 ml of tetrahydrofuran and stirred for 24 hours to completely dissolve the GPC. After measurement using a gel permeation chromatography instrument (Waters 2414, Waters), the standard samples (S-1.3, S-2.8, S-6.8, S-20, S-51, S-126, S-282 S-791, S-1640 and S-258, Showa Denko kk) were used to draw and convert the calibration curve.

division	Vinyl acetate content (wt%)	Degree of polymerization (DP)	Weight average molecular weight (g / mol)	Number average molecular weight (g / mol)	Polydispersity index
Example 1	5.36	1250	164294	70590	2.33
Example 2	5.41	1260	164010	70089	2.34
Example 3	5.47	1250	160978	70319	2.29
Example 4	5.52	1240	162276	72075	2.25
Example 5	5.58	1260	161423	69887	2.31
Example 6	5.60	1250	163641	72093	2.27
Example 7	5.65	1270	162539	74949	2.17
Example 8	4.09	1260	164328	70046	2.35
Example 9	7.00	1240	161630	65890	2.40
Example 10	5.29	1250	164191	69484	2.36
Comparative Example 1	5.5	1260	161865	64772	2.50
Comparative Example 2	-	1270	168320	66790	2.52
Comparative Example 3	4.71	1250	165680	68690	2.41
Comparative Example 4	3.56	1260	164289	67730	2.46
Comparative Example 5	8.02	1220	160417	63914	2.51
Comparative Example 6	11.96	1190	161059	63093	2.55
Comparative Example 7	5.13	1240	168448	70012	2.41
Comparative Example 8	N / A	N / A	N / A	N / A	N / A

 As shown in Table 1, the vinyl chloride-vinylacetate copolymers of Examples 1 to 10 according to an embodiment of the present invention showed a vinyl acetate-derived unit content and a polydispersity index in a desired range. The vinyl chloride-vinylacetate copolymer or vinyl chloride polymer of Examples 1 to 7 showed a polydispersity index higher than 2.4, which is the maximum value of the desired range, and in Comparative Example 8, the copolymer was exhibited due to latex aggregation. Was not properly formed and measurement was impossible.

Here, the vinyl chloride-vinylacetate copolymers of Comparative Example 1 and Comparative Example 3 were prepared under the same conditions as in Example 1 except that the entire amount of the vinyl chloride monomer was added before the start of polymerization, and Comparative Examples 4 to The vinyl chloride-vinylacetate copolymer of Comparative Example 6 was prepared under the same conditions as in Example 1 except that the vinyl acetate content was outside the range indicated in the present invention, and the vinyl chloride- of Comparative Example 7 and Comparative Example 8- The vinyl acetate copolymer is prepared under the same conditions as in Example 1 except that the fractional injection ratio of the vinyl chloride monomer is outside the range shown in the present invention.

The above results indicate that in order to obtain a vinyl chloride-vinylacetate copolymer having a polydispersity index desired in the present invention, not only the content of vinyl acetate but also the addition method of the vinyl chloride monomer and the ratio according to the time of introduction, that is, participate in the polymerization during the polymerization. This means that the ratio between monomers can be important.

Experimental Example 2

Processing characteristics of the workpieces manufactured using the vinyl chloride-vinylacetate copolymers prepared in Examples 1 to 10 and Comparative Examples 1 and 3 and 8 and the vinyl chloride polymer prepared in Comparative Example 2, and In order to analyze the tensile strength characteristics, the viscosity of the plastisol before the low temperature processing, the tensile strength during the low temperature processing, the tensile elongation and the transparency were analyzed. The results are shown in Table 2 below.

First, 60 g of dioctylphthalate and 2 g of a stabilizer (SONGSTAB BZ-119, Songwon Industry) were added to 100 g of each copolymer or polymer, and stirred for 10 minutes with a stirrer to prepare each plastisol. The prepared plastisol was applied on a glass plate and spread out to a thickness of 2 mm using a film applicator, and the sheet was left for 30 minutes in an oven at 130 ° C. (Mathis Oven CH-8156) to prepare each sheet. Each sheet was manufactured in a long dumbbell shape (Dogbone, width 6.25 mm, thickness 1.5 mm) specimens and cross head speed 500 using a tensile strength meter (Model: 2010, Zwick, Inc.) in accordance with ASTM D638. After pulling at mm / min, the tensile strength and elongation (%) of the points at which the specimens were cut were measured.

A portion of each plastisol prepared before low temperature processing was aged for 1 hour in a thermostat at 25 ° C. and 50% relative humidity, and then viscosity at 6 rpm with spindle LV-3 (# 63) using Brookfield Viscosity LV type. Was measured.

Transparency of each sheet was measured using Haze-gard plus (BYK).

division	Viscosity (cP)	Tensile Strength (MPa)	% Elongation	transparency(%)
Example 1	6,200	10.33	697	82.7
Example 2	7,000	12.03	778	86.2
Example 3	5,500	13.11	893	89.2
Example 4	6,900	13.47	824	89.6
Example 5	5,300	12.89	834	88.0
Example 6	5,900	13.18	907	89.4
Example 7	5,800	13.71	933	89.7
Example 8	5,400	10.03	623	81.4
Example 9	8,400	11.43	1010	90.3
Example 10	6,700	10.3	669	82.1
Comparative Example 1	6,300	9.3	662	77.4
Comparative Example 2	5,300	6.2	493	74.8
Comparative Example 3	5,700	8.92	654	78.9
Comparative Example 4	5,400	8.12	614	78.1
Comparative Example 5	9,400	9.7	1016	90.4
Comparative Example 6	12,500	8.26	1123	90.6
Comparative Example 7	6,900	9.91	645	81.3
Comparative Example 8	N / A	N / A	N / A	N / A

As shown in Table 2, the processed article prepared using the vinyl chloride-vinylacetate copolymer of Examples 1 to 10 according to an embodiment of the present invention is Comparative Example 1, Comparative Examples 3 to Compared with the vinyl chloride-vinylacetate copolymer and the vinyl chloride polymer of Comparative Example 2, the tensile strength and elongation were markedly increased while showing excellent transparency overall.

Specifically, the vinyl acetate-derived unit is included in the content range shown in the present invention, but the polydispersity index of Comparative Example 1, Comparative Example 3 and Comparative Example 7 outside the range shown in the present invention is vinyl chloride-vinylacetate air Workpieces manufactured using the coalescence had reduced transparency up to a level of 85% compared to the workpieces manufactured using the vinyl chloride-vanyl acetate copolymers of Examples 1 to 10, and low-temperature tensile strength decreased up to a level of 65%. It became.

In addition, in the case of the processed product manufactured using the vinyl chloride polymer of Comparative Example 2 containing no vinyl acetate derived unit, the transparency of the vinyl chloride-vinylacetate copolymer of Examples 1 to 10 was 82.3% to 92%. Tensile strength is 45% to 62%, and elongation is significantly reduced to 49% to 79%.

In addition, Example 8 and Example 9 also in the case of the workpiece manufactured using the vinyl chloride-vinylacetate copolymer of Comparative Examples 4 to 6 containing a vinyl acetate derived unit outside the range of 4% by weight to 7% by weight. As a result of comparison with the processed product manufactured using the vinyl chloride-vinylacetate copolymer of, the processed product manufactured using the vinyl chloride-vinylacetate copolymer of Comparative Example 4 was used the vinyl chloride-vinylacetate copolymer of Example 8. The elongation was reduced, the transparency decreased by 4%, and the tensile strength was significantly reduced to 19%. In addition, elongation and clarity of the processed product prepared using the vinyl chloride-vinylacetate copolymer of Comparative Example 5 and Comparative Example 6 were similar to those of the processed product manufactured using the vinyl chloride-vinylacetate copolymer of Example 9. However, the low temperature tensile strength significantly decreased to 85% and 72% levels, and the viscosity increased sharply.

The results indicate that the polydispersity index and the content of vinyl acetate derived units play an important role in the development of excellent low temperature tensile strength properties while affecting the processing properties (transparency) improvement. Accordingly, the vinyl chloride-vinylacetate copolymer according to an embodiment of the present invention has a polydispersity index adjusted while including a vinyl acetate derived unit in a specific content range, thereby providing excellent processing properties and significantly improved low temperature tensile strength. Can exhibit characteristics.

Claims (17)

1. The polydispersity index (PDI) is 2.1 to 2.4 in the degree of polymerization 1200-1300,

   Vinyl chloride-vinylacetate copolymer comprising 4 to 7% by weight of vinyl acetate derived units.
2. The method according to claim 1,

   Wherein said copolymer has a polydispersity index (PDI) of greater than 2.1 and less than 2.3.
3. The method according to claim 1,

   The copolymer has a vinyl chloride-vinylacetate copolymer having a weight average molecular weight (Mw) of 160,000 g / mol to 165,000 g / mol.
4. The method according to claim 1,

   Wherein said copolymer comprises from 5% to 6% by weight of vinyl acetate derived units of vinyl chloride-vinylacetate copolymer.
5. The method according to claim 1,

   The copolymer has a tensile strength of 10 MPa to 14 MPa,

   The tensile strength of the vinyl chloride-vinylacetate copolymer is measured according to ASTM D638 after the copolymer was heat-treated at 130 ° C. for 30 minutes to prepare a specimen having a width of 6.25 mm and a thickness of 1.5 mm.
6. The method according to claim 1,

   The copolymer has an elongation (%) of 600% to 1,100%,

   The elongation of the vinyl chloride-vinylacetate copolymer is measured according to ASTM D638 after the copolymer was heat-treated at 130 ° C. for 30 minutes to prepare a specimen having a width of 6.25 mm and a thickness of 1.5 mm.
7. The method according to claim 1,

   The copolymer has a transparency (%) of 80% to 92%,

   The transparency is a vinyl chloride-vinylacetate copolymer which is measured by a haze meter after the copolymer was heat-treated at 130 ° C. for 30 minutes to prepare a specimen having a width of 6.25 mm and a thickness of 1.5 mm.
8. 1) 50% to 80% by weight of vinyl chloride monomer in 100% by weight of the total amount of vinyl chloride monomer and 5.5 parts by weight to 10 parts by weight of vinyl acetate are mixed and homogenized based on 100 parts by weight of the total amount of vinyl chloride monomer to start the polymerization reaction. Making;

   2) A method for preparing the vinyl chloride-vinylacetate copolymer of claim 1 comprising the step of adding 20 to 50% by weight of a vinyl chloride monomer after the polymerization reaction to participate in the polymerization reaction.
9. The method according to claim 8,

   The vinyl chloride monomer of step 2) is a method of producing a vinyl chloride-vinylacetate copolymer is a batch of 20% to 50% by weight at a time of 1/3 or more of the total reaction time.
10. The method according to claim 8,

    The vinyl chloride monomer of step 2) is a vinyl chloride-vinylacetate air in which 20 to 50% by weight is continuously added at an input rate of 3 to 17% by weight from the time of 1/3 or more of the total reaction time. Process for the preparation of coalescing.
11. The method according to claim 8,

    The vinyl chloride monomer of step 1) and the vinyl chloride monomer of step 2) is a method of producing a vinyl chloride-vinylacetate copolymer having a weight ratio of 4: 1 to 1: 1.
12. The method according to claim 8,

    The polymerization reaction is a method of producing a vinyl chloride-vinylacetate copolymer that is carried out under a temperature range of 30 ℃ to 70 ℃.
13. The method according to claim 8,

    Wherein said polymerization is carried out in the presence of an emulsifier and a polymerization initiator.
14. The method according to claim 13,

    The emulsifier is one selected from the group consisting of linear alkylbenzene sulfonates, sodium lauryl sulfate, lauryl benzene sulfonic acid, alpha-olefin sulfonate, sodium lauryl epoxidized sulfate, sodium octadecyl sulfate and sodium lauryl ether sulfate. The manufacturing method of the vinyl chloride-vinylacetate copolymer which is the above.
15. The method according to claim 13,

    The polymerization initiator is a method for producing a vinyl chloride-vinylacetate copolymer which is an oil-soluble polymerization initiator.
16. The method according to claim 13,

    The polymerization initiators are cumenehydro peroxide, diisopropyl benzene hydroperoxide, azobis isobutyronitrile, tertiary butyl hydroperoxide, paramentane hydroperoxide, benzoyl peroxide and di-2-ethylhexyl peroxy Method for producing a vinyl chloride-vinylacetate copolymer which is at least one selected from the group consisting of dicarbonate.
17. The method according to claim 8,

    The manufacturing method is a method of producing a vinyl chloride-vinylacetate copolymer further comprises one or more of the steps of washing, flocculating and drying after the step 2).