JP2615164B2 - Vinyl chloride multi-component copolymer resin - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an improved novel vinyl chloride-based multi-component copolymer resin.

More specifically, the present invention relates to a vinyl chloride-based multi-component copolymer resin having substantially no copolymer component composition distribution and having a substantially uniform composition.

[Conventional technology and problems]

Although it is obvious that a very large amount of vinyl chloride resin is used for various applications, a disadvantage is that a large amount of a plasticizer must be added in order to perform free processing. For example, blow-molded bottles and the like cannot expect the barrier properties inherent to vinyl chloride resin due to the plasticizer contained therein.

On the other hand, in order to reduce or eliminate the use of a plasticizer, there have been many proposals to increase the utilization by internal plasticization by copolymerization with another monomer.

For example, a copolymer resin with vinyl acetate (so-called polyvinyl chloride resin) is often used as a coating material because it is easily dissolved in an organic solvent. However, this means that a problem arises in the solvent resistance.

Also, a copolymer resin of vinyl chloride and vinylidene chloride is well known, and this resin is a so-called saran resin having a vinyl chloride content of at most about 20% or a resin having a vinylidene chloride content of only 20%. , And those with intermediate compositions are rare. The reason is that, when copolymerized by a conventionally known polymerization method, an intermediate composition cannot be formed on average, and the composition is biased toward vinylidene chloride from the one biased toward vinyl chloride. This is because only a non-characteristic copolymer resin having a wide composition distribution was obtained. Further, polymerization time is long in any composition range, which is disadvantageous in productivity.

In addition to these examples, there are various vinyl chloride-based copolymer resins, but if any of them has features, on the other hand, it also has disadvantages, and still further various new copolymer resins. Is desired.

[Means for solving the problem]

In view of such a situation, the present inventors provide, among other things, a barrier property, a chemical resistance property, and a gloss property, which are features of vinylidene chloride resin, as much as possible. After diligent research into developing and providing vinyl chloride / vinylidene chloride copolymer resin, the composition of each fraction obtained by further introducing third and fourth monomers and separating the obtained resin by molecular weight Are also substantially constant and are indistinguishable by solubility, i.e., this generally indicates that the composition distribution of the copolymer is substantially absent or very small.

Such a copolymer resin having a uniform composition can be extruded by drastically reducing the amount of plasticizer, and a container or film / sheet with high barrier properties can be obtained.
A low plasticizer paste resin can be made, and its resin film shows excellent flame retardancy without plasticizer bleed,
Furthermore, while having excellent solubility, once a coating film is formed, it exhibits excellent solvent resistance, etc., and exhibits excellent performance in various application fields where vinyl chloride resins are currently used. It has been found that the present invention has been completed.

That is, the present invention provides: (A) 30 to 80 parts by weight of vinyl chloride, (B) 15 to 65 parts by weight of vinylidene chloride, and (C) 5 to 5 parts in total of other monomer components.
55 parts by weight, a total of 100 parts by weight of a copolymer resin, wherein the composition of each fraction to be separated by molecular weight is also substantially constant, and the resin is to be separated by solubility. The present invention relates to a vinyl chloride-based multi-component copolymer resin, which is a copolymer that cannot be obtained.

In the present invention, other monomers (C) copolymerized with vinyl chloride (A) and vinylidene chloride (B) include vinyl esters of aliphatic carboxylic acids such as vinyl acetate and vinyl propionate; acrylic acid And unsaturated aliphatic carboxylic acids such as methacrylic acid, itaconic acid, crotonic acid, maleic acid, fumaric acid and maleic anhydride; and their aliphatic alcohol esters; styrene, (meth) acrylonitrile and (meth) acrylamide. Olefins having one polymerizable double bond; or dienes having two copolymerizable double bonds such as isoprene and butadiene and their chlorides such as chlorobutadiene; glycidyl (meth) acrylate, allyl glycidyl ether and the like Having a copolymerizable double bond and an epoxy group; divinylbenzene and divalent fats Monomers having two positions copolymerizable double bonds in the molecule as (meth) acrylic acid ester of a family alcohol; vinyl sulfonic acid, styrene sulfonic acid,
2-sulfoethyl methacrylate, 3-sulfopropyl methacrylate, methallyl sulfonic acid, 2-acrylamido-2-methylpropane sulfonic acid, etc. and their Na, k
Or, among the salts of NH _{4 and} the like, properties that affect processing characteristics such as a glass transition point and a softening point of a generated copolymer resin,
The selection is made in consideration of practical properties of the processed product of the copolymer resin such as solvent resistance and blocking resistance.

Generally, resins obtained by copolymerization, for example, radical copolymerization, are composed of copolymers having a distribution in composition. The reason is that, in the copolymerization reaction, each monomer has a specific reactivity ratio, and even if monomers are charged and reacted at a certain ratio in the reactor, the composition of the polymer which is generated every moment as the polymerization progresses Does not match the monomer charge ratio. Some monomers polymerize, the composition of the remaining monomers changes, and then the composition of the next polymer changes, thus changing the composition of the remaining monomers, and the composition of the polymer produced at the next moment Changes again. Thus, while the polymerization proceeds, the composition of the polymer formed every moment changes. This is called a copolymer composition drift. Thus, a distribution occurs in the composition.

In a vinyl chloride resin having vinylidene chloride as the second component and other monomers as the third and fourth components, the reactivity ratio between vinyl chloride and vinylidene chloride is far apart, so that it is conventionally known. In the polymerization method, only those having a large composition distribution due to this drift were obtained, and industrially useful resins could not be obtained.However, in a special emulsion polymerization reaction method, the total amount of vinyl chloride and vinylidene chloride When a part is charged into the reactor and vinylidene chloride and other monomers are continuously added at the start of the polymerization, the composition in the reactor becomes constant every moment, and there is almost no drift of the copolymer composition. A resin whose distribution is extremely narrow and is not practical and has a substantially uniform composition can be obtained.

In the present invention, such a copolymer composition distribution is extremely narrow,
The present invention relates to a vinyl chloride-based resin that can be referred to as having substantially uniform composition.

The resin of the present invention, in addition to the versatility of a vinyl chloride resin, provides good workability without the need for reducing or using a plasticizer, and has features such as barrier properties, solvent resistance, and gloss of vinylidene chloride resin. It gives a variety of practical performances by selecting the third and fourth monomers, and as it is as a molding resin, medical equipment such as blood bags, cups and bottles for processed foods, or films Although it has good solubility, the coating liquid is also used as a resin for coating and raw materials for coatings, taking advantage of its excellent solvent resistance. Without being used, it is used as it is in the form of latex for coating and various binders. Further, it is useful as a polymer modifier which is kneaded with a vinyl chloride resin to improve processability.

In the resin of the present invention, when the content of vinylidene chloride is 15 parts by weight or less, internal plasticizing effect and solvent resistance, gloss and the like,
The effect of copolymerizing vinylidene chloride cannot be expected.
On the other hand, if it exceeds 65 parts by weight, it becomes close to a conventionally known vinylidene chloride resin. Regarding the amount of the other monomer to be introduced, if the total amount of one or more of them is 5 parts by weight or less, the effect of introducing the monomer is not clear. Lose versatility.

The molecular weight of the resin of the present invention is set to a value suitable for its use. In other words, in the case of coating or coating raw materials that are dissolved in an organic solvent, if the viscosity of the solution is too high, it is inconvenient. Therefore, a relatively low molecular weight, for example, about 20,000 to 50,000 in number average, and higher for molding, Latex may be even higher.

The resin of the present invention which can be produced by the above-mentioned method is characterized in that it has substantially no composition distribution and can have a relatively high molecular weight of 50,000 to 100,000.

The molecular weight is a value measured by gel permeation chromatography (GPC) using polystyrene as a standard.

In the resin of the present invention, when using a large-capacity column for preparative separation by GPC and performing elemental analysis on each of the fractions fractionated into 4 to 5 sections, any fraction is within the range of measurement variation. It also shows a substantially uniform composition, which is also substantially constant.

For elemental analysis, carbon, hydrogen, and nitrogen are determined by a conventional method such as an NC analyzer, chlorine is determined by an oxygen flask combustion method, and sulfur is determined by atomic absorption analysis.

Furthermore, in the resin of the present invention, the solubility ratio is in a narrow range from the start to the end of elution by the solubility separation operation described below, and the resin cannot be separated by the solubility.

Solubility fractionation: 0.1 g of resin is dissolved in 10 ml of tetrahydrofuran, mixed well with glass beads having a particle size of about 1 mm, and the solvent is volatilized. Glass beads surface-coated with the obtained resin are filled in a glass cylinder equipped with a constant temperature jacket, and the solubility is fractionated using a tetrahydrofuran (good) / methanol (poor) eluent. Starting from 100% by volume of the poor solvent, the ratio of good / poor solvent is changed in 5% by volume steps and eluted to fractions of 21 to 100% by volume of the good solvent.

Hereinafter, the present invention will be described in more detail by way of examples, but these do not limit the scope of the present invention.

In the following examples, all parts are parts by weight. Example 1 Composition ratio: vinylidene chloride / methyl acrylate = 64/36
A latex having an average particle size of 27 nm as measured by laser light scattering was used as a seed latex, and 60 parts of vinyl chloride and 3.2 parts of vinylidene chloride were charged into a glass-lined iron-made reaction vessel, and the temperature was raised to 50 ° C. A mixture of the prepared 11.8 parts of vinylidene chloride, 20 parts of methyl methacrylate, and 5 parts of acrylic acid, sodium persulfate, sodium bisulfite, and sodium alkylbenzene sulfonate, each aqueous solution were continuously added, emulsion polymerization was performed, and salting out was performed. The resin was washed with water and dried to obtain a resin. The results of resin identification are shown in Table 1 below.

The resin of the present example, for example, as a coating agent for moisture-proof cellophane, shows excellent solubility compared to a vinyl chloride resin copolymerized with vinyl acetate which is currently used.
Once the coating film was formed, it was excellent in solvent resistance, and the suitability for printing lamination processing, which had a problem with existing resins, was significantly improved.

Comparative Example 1 In Example 1, instead of initially charging vinyl chloride and part of vinylidene chloride, the entire amount of the monomer used was charged. After 8 hours, the internal pressure of the reactor was high and there was no sign of a decrease, so the addition of sodium persulfate and sodium bisulfite was continued. The pressure began to decrease only after 65 hours, but the reaction was stopped when the gauge pressure became 0 because it was extremely slow. Only a small amount of vinyl chloride remained.

When the resin obtained by salting out, washing and drying was dissolved in tetrahydrofuran, it did not completely dissolve, and the solution became cloudy.
The resulting solution was filtered through a 2G glass filter, and the clear solution was subjected to solubility fractionation. As a result, all 21 fractions in 5% steps from 100% tetrahydrofuran to 100% methanol were eluted. This resin did not dissolve in the solvent system for vinyl chloride vinyl chloride resin, and had poor practicality as a coating resin.

Comparative Example 2 In Example 1, instead of first adding vinyl chloride and vinylidene chloride, all monomers were mixed and continuously added over 30 hours, and sodium persulfate and sodium bisulfite were also added. I continued. The surfactant was prepared in Example 1.
When the same amount was added, the connection was stopped.

The resin obtained by salting out, washing and drying was dissolved in tetrahydrofuran, and the molecular weight was measured.
The molecular weight was 18 thousand, and the weight average was 63 thousand. According to the UV detector, the acrylic acid content was high on the low molecular weight side.

Further, when the solubility fractionation was also performed, elution was immediately observed from good / poor = 0/100, and the entire amount was eluted at 40/60. The fractionation (elution) curve has a peak at 25/75 to 30/70 and is considered to have a narrower composition distribution than the resin of Comparative Example 1.
It does not reach the resin of Example 1.

Since this resin was dissolved in a solvent for vinyl chloride vinyl chloride resin, it was evaluated together with Example 1 and found that the solvent resistance was insufficient, the adhesion between the coating film and cellophane was poor, and the coating films were heated together. Upon sealing, the sealing strength was low, and this point was also impractical.

Example 2 The composition of the charged monomers was 40 parts of initially added vinyl chloride, 11.9 parts of vinylidene chloride, and 38.1 parts of vinylidene chloride, 9 parts of acrylonitrile, and 9 parts of 2-acrylamido-2-methylpropanesulfonic acid. Except for using 1 part of soda, emulsion polymerization, salting out,
The resin was washed with water and dried to obtain a resin. Table 2 below shows the results of resin identification.
It was shown to.

The resin of this example was compared with a PVC resin used as a binder for magnetic powder for a magnetic recording medium such as a video tape.

The performance required of the main binder resin of the so-called coating type magnetic recording medium is diversified, but is ultimately limited to two points of durability and dispersibility of the magnetic powder. However, a fatal drawback of the PVC-based resin is that decomposition at high temperature, that is, dehydrochlorination is apt to occur.

The resin of the present example was capable of well dispersing magnetic powder, which has been becoming finer and more difficult to disperse in recent years, and also greatly suppressed high-temperature dehydrochlorination.

Comparative Example 3 A resin obtained by polymerizing a monomer having the same composition as in Example 2 in the same manner as in Comparative Example 1 has a wide solubility distribution, does not dissolve in a solvent having a composition generally used for preparing a magnetic paint, and has practical utility. There was no one.

Comparative Example 4 A resin obtained by polymerizing a monomer having the same composition as in Example 2 in the same manner as in Comparative Example 2 has a somewhat narrow solubility distribution,
It was still wide and the molecular weight was small. For the time being, a magnetic paint could be prepared, but the coating film was easily dehydrochlorinated and had poor durability.

Example 3 Example 1 was repeated except that the charged monomer composition was 60 parts of initially added vinyl chloride, 6.7 parts of vinylidene chloride, and 18.3 parts of vinylidene chloride and 15 parts of butyl acrylate.
Emulsion polymerization was carried out in the same manner as described above, salting out, washing with water and drying were performed to obtain a resin. The results of the identification are shown in Table 3.

In the resin of this example, even if the required amount of the plasticizer was significantly reduced as compared with the vinyl chloride resin, good moldability was obtained. Did not.

Comparative Example 5 Water 15 was placed in a glass-lined iron pressure-resistant reaction vessel.
0 parts, 1 part of hydroxymethylpropylcellulose, 0.3 part of lauroyl peroxide and all of the monomers of Example 3 were charged, and suspension polymerization was carried out. To prevent the polymerization from becoming a runaway reaction, the temperature was kept at 40 ° C. for the first 20 hours and then at 50 ° C. for 60 hours. The internal pressure of the reactor was high, a large amount of vinyl chloride remained, and it was considered that the polymerization conversion had not progressed. The temperature was further raised to 60 ° C., but only the internal pressure increased as the temperature rose, and there was no sign that the reaction was proceeding. Among them, judging from the decomposition half-life of lauroyl peroxide, it was judged that there was no longer any initiator that could substantially proceed with polymerization, so the temperature was lowered and unreacted monomers were drawn out to the blowdown tank. .

When the amount of the initiator was increased, the initial reaction rate was slightly increased, but it was not possible to polymerize all of the monomers merely by lowering the molecular weight. Most of the unreacted monomer was vinyl chloride, but this was ignored to obtain a product resin.

When the obtained resin was dissolved in tetrahydrofuran, it did not become completely transparent but became cloudy. Solubility fractionation was performed on those filtered through a 2G glass filter.
Elution was observed in all compartments with a good / poor solvent ratio. If this resin was heated and kneaded to obtain a sample in the same manner as in Example 3, browning began during that time, and the thermal stability was poor.

Example 4 The same procedure as in Example 1 was carried out except that the charged monomer composition was 50 parts of initially added vinyl chloride, 8.8 parts of vinylidene chloride, and 21.2 parts of vinylidene chloride and 20 parts of butadiene. After emulsion polymerization, salting out, washing with water and drying were performed to obtain a resin. The results of the identification are shown in Table 4 below.

The resin of this example uses a resin whose monomer is inexpensive like vinyl chloride and the like, and further, greatly reduces the amount of plasticizer,
A stretch film which is advantageous in terms of production cost is provided.

When compared with a commercially available stretch film made of a vinyl chloride resin, all of the practical strength characteristics as a packaging film were equivalent to those of a commercial product, and showed a very low elution amount. The barrier properties (moisture permeability) were also very good. The barrier property is an advantage expected from the fact that the resin composition of the present invention copolymerizing vinylidene chloride and the amount of plasticizer used are small.

Example 5 The composition of the charged monomers was 30 parts of initially added vinyl chloride and 10 parts of vinylidene chloride, and the added mixture was 30 parts of vinylidene chloride, 15 parts of styrene, 12 parts of acrylonitrile, and 3 parts of N-phenylmaleimide. The resin was obtained by emulsion polymerization, salting out, washing with water and drying in the same manner as in Example 1 except that the amount was changed to parts. Table 5 shows the results of the identification.

Various food and beverage containers such as blow molded bottles of soft vinyl chloride resin with a plasticizer are widely used,
There is a problem that the plasticizer is eluted into the contents and a problem that the barrier property inherent to the vinyl chloride resin is completely lost due to the large amount of the plasticizer.

The resin of this example exhibited good moldability with the addition of a smaller amount of plasticizer, the barrier properties of the obtained container were extremely high, and the disadvantage of the vinyl chloride resin was eliminated.

Comparative Example 6 In the same manner as in Comparative Example 5, the monomer of Example 5 was subjected to suspension polymerization. Again, the entire amount of vinyl chloride could not be polymerized, indicating that the resulting resin had a wide solubility distribution and a wide resin composition distribution.

When this resin was molded in the same manner as in Example 5, the parison coming out of the extruder had a brown color,
Moldability was also poor.

Example 6 The composition of Example 1 was changed except that the composition of the charged monomers was 40 parts of initially added vinyl chloride and 13.3 parts of vinylidene chloride, and the addition mixture was 36.7 parts of vinylidene chloride and 10 parts of methyl acrylate. Similarly, emulsion polymerization, salting out, washing with water, and drying were performed to obtain a resin. The results of the identification are shown in Table 6 below.

The so-called PVC paste, which is a mixture of vinyl chloride resin and a large amount of plasticizer on a mount, is printed and embossed, and is widely used as high-grade wallpaper. , A large amount of flame retardant is also added.

However, since the resin of the present embodiment can obtain a paste with a smaller amount of plasticizer, the plasticizer migrates to the surface of the wallpaper over time and becomes easily stained. Absent. From the viewpoint of the resin composition and the small amount of the plasticizer, the flame retardant may be hardly added. Further, the wallpaper made of the resin of the present invention was excellent in antifouling property and cleared flameproofing first grade, while PVC wallpaper was flameproofing second grade.

For comparison, Table 7 below summarizes the results of molecular weight and solubility fractionation of the resulting resin for Example 1 and Comparative Examples.

[Effects of the Invention] In addition to the versatility of a vinyl chloride-based resin, the resin of the present invention provides good processability that requires less or no plasticizer.

The vinylidene chloride resin has characteristics such as barrier properties, solvent resistance, and gloss.

The selection of the third and fourth monomers gives versatile practical performance.

It can be used as it is as a molding resin in medical equipment such as blood bags, cups and bottles for processed foods, or films.

Although it has good solubility, it is also used as a resin for coating and as a raw material for coatings, taking advantage of its excellent solvent resistance after coating.

It is used for coating and various binders in the form of a latex as it is without being converted into a resin powder after emulsion polymerization.

Further, it is effective as a polymer modifier which is kneaded with a vinyl chloride resin to improve processability.

Claims (1)

(57) [Claims] 1. A total of 100 parts by weight of (A) 30 to 80 parts by weight of vinyl chloride, (B) 15 to 65 parts by weight of vinylidene chloride, (C) 5 to 55 parts by weight in total of other monomer components. Wherein the composition of each of the fractions fractionated by molecular weight is also substantially constant, and is a copolymer that cannot be fractionated by solubility. A vinyl chloride-based multi-component copolymer resin.