JPS58208306A - Production of vinyl chloride resin - Google Patents

Abstract

PURPOSE:To obtain a vinyl chloride resin excellent in low-temperature heat sealability, by adding vinyl chloride in portions in copolymerizing vinyl chloride with vinyl acetate and an alpha,beta-unsaturated dicarboxylic acid (anhydride). CONSTITUTION:At least 97wt% mixture containing vinyl chloride and vinyl acetate at a weight ratio of 55-70:45-30 is polymerized with below 3wt% alpha,beta- unsaturated dicarboxylic acid or its anhydride copolymerizable therewith at 50- 80 deg.C in an organic solvent (e.g., ethyl acetate) in the presence of a polymerization initiator (e.g., lauroyl peroxide). Vinyl chloride corresponding, in amount, to 10-30wt% of the total amount of the initially fed monomers is added continuously or in portions after the conversion of the initial feed has reached at least 50wt%, and the polymerization is brought to completion.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improved method for producing a saponified hinyl-hinyl acetate-based co-merchandising resin.

Conventionally, one of the methods for imparting 4ID resistance and heat sole properties to cellophane is to use a uniform solution (which is a mixture of a hinyl chloride-vinyl acetate-based strawberry solution, a moisture-proofing agent such as paraffin, and, if necessary, a stabilizer, etc.). There is a method of forming a uniform thin film on the Cehino Ano surface by soaking cellophane in oil (paint) and drying it.
Is cellophane used for the exterior of cigarettes and other products, and in that case is it usually adhesive processed by thermocompression bonding, the so-called heat-nol processing method?J).

Hinyl chloride/hinyl acetate, which is used to impart heat-nol properties, is available in the form of a resin solution41, which is the simplest manufacturing method and commercially available as a solution. Milling f1 as the speed increases
It has become impossible to fully satisfy the required quality from 1. That is, sufficient Y&adhesion strength can be obtained with a short heat-1-seal time, and a non-adhesive surface layer can be obtained when stacking packaged products!
There is an increasing demand for resin properties that do not cause the so-called flocculation phenomenon in fusion bonding.In other words, the temperature at which flocculation occurs must be as high as possible, There is an increasing demand for resins that have resin properties that allow peel processing at as low a temperature as possible, as well as temperature dependence of heat seal strength. Vinyl chloride acid-based resins produced by polymerization method (-) have a low degree of polymerization due to chain transfer of solvent and \ in the polymerization group, and due to constraints on solvent solubility and vinyl acetate. It is possible to lower the proportion of tc in the total μ-body by other methods such as emulsion polymerization or suspension polymerization.
Therefore, only relatively soft (low softening temperature) resins can be obtained.It is easy to lower the P1-seal temperature, but it is difficult to raise the FLORAKING ri□111 temperature. So, it is difficult to satisfy the 1. V1-\1.7) requirements for the resin described above.

As a result of various studies, we found that the processing temperature at which a fully satisfactory sealing strength is achieved is based on the heat of the resin. It was discovered that the softening temperature, that is, the average vinyl acetate content range in the resin, and the anti-flocking temperature largely depended on the high vinyl acetate-containing polymer produced at the end of the polymerization reaction and contained in the resin, and The present invention has revealed that it is possible to prevent the formation of such polymers in ordinary solution polymerization methods by adding a few practical measures. 3. That is, the present invention is directed to a ternary copolymer consisting of vinyl chloride, vinyl acetate, their lj j, i, and their polymerization i + J function j (α, t)-unsaturated dicarfonic acid or its anhydride in the presence of a solvent. In the polymerization, after the polymerization reaction rate of the monomer charged before polymerization reaches 50%, vinyl chloride of 10 to 30% by weight of the monomer monomer charged before polymerization is added continuously or in parts to the polymerization system. This relates to a polymerization method characterized by the addition of polyvinyl acetate into the polymer, which prevents the formation of high vinyl acetate-containing polymers that are formed in the late stage of polymerization, has high resistance to vinyl acetate, and has excellent low-temperature heat sealability. The present invention will now be described in detail.

In general, in copolymerization reactions using F bodies with different F polymerization reaction rates, in order to make the composition distribution of the produced polymer homogeneous, the composition of the reaction single stars present in the polymerization group must be kept constant. This is basic knowledge for those involved in copolymerization reactions, and an example is given in the case of vinyl chloride copolymerization, for example, in Japanese Patent Publication No. 47-17625. ,l, ;6
As shown in this example, the combination of acetic acid and vinyl monochloride (L7) is homogenized using 5υ8゛Ruri11,1 at the beginning of the reaction rate. Now, let's look at the composition again. (In order to obtain a small polymer, most of the vinyl chloride 141i used must be added over a long period of time to the polymerization process.) However, according to the method of the present invention, it is possible to achieve commercial production without adopting such known impractical methods. A vinyl chloride-vinyl acetate co-component having a good balance of blocking resistance and processability can be obtained by a simple and simple addition method which can be easily put to practical use.

Copolymerization of vinyl chloride, vinyl acetate, and maleinoic anhydride solution for the purpose of cellophane Table 1/+1 treatment is as follows:
Usually, polymerization is carried out in an acetate ester solvent under polymerization temperature condition F of 40 to 70°C using a polymerization initiator. In this case, the charging ratio of vinyl chloride monomer and vinyl acetate monomer is usually 70:30 to 60:40 mW ratio3. For example, even if the polymerization is started at a ratio of 65:35, the vinyl acetate content in the polymer produced at the initial stage of polymerization is 25% or less, and the polymerization reaction rate is 80%. The average vinyl acetate content of all the polymers remains at about 30% by weight, making it a polymer with a wide composition distribution and 1. This resin has heat sealing strength temperature dependence or flow I -C' and low flocking resistance temperature -C. Heat sealing strength temperature dependence or high speed peak 1 - Suitable for sole processing, - force and anti-blocking temperature are fully satisfactory in actual practice.
) contains 25 to 30% of \V hydrogenated acetic acid.
It has been found from the study results of the inventors that it is sufficient to use a resin that is , and does not contain more than 41% of vinyl acetate units in the total polymer. Therefore, either the composition of unreacted monomers changes as the polymerization reaction progresses, or new vinyl chloride monomers are added to the polymerization system before reaching a composition that produces a polymer with a vinyl acetate M content of 40 tonne. The key point of the present invention is to increase the body size by 1+++. That is, when polymerization is started at a vinyl chloride-vinyl acetate ratio of 55 to 70: 45 to 30, the roux at the start of addition of vinyl chloride 111lfi is as follows:
Less or less polymerization + iiJ preparation preparation - polymerization reaction rate is 50
%.I), preferably 60% or more. In addition, at this time, the amount of vinyl chloride monomer added in the polymerization system is 10 to 30 LX2 of the total amount of monomer charged before polymerization.
, preferably 15-25% - 111%, additional l
If the amount of vinyl chloride exceeds 30 kt%, the content of vinyl chloride in the polymer formed after that increases, which may reduce the solubility of the solvent. Efficiency in reactor usage too! Sewing 1, on the other hand, 10
If the addition is less than the weight, the effect of the present invention will be insufficient and the object of the present invention will be difficult to achieve.

Addition of vinyl chloride during polymerization may be carried out continuously, or 1. Alternatively, it may be carried out all at once or in parts, or it may be added all at once or in parts after polymerization has proceeded as much as possible.
That is, in the present invention, the polymerization reaction rate of the monomer used before polymerization is 50%.
It is preferable to add it all at once or in parts after reaching 60% or more.

The resin according to method θ of the present invention is used for surface treatment of anti-41D cellophane, etc. For such uses, maleinoic acid,
A resin obtained by slightly copolymerizing an unsaturated dicarboxylic acid such as fumaric acid or its anhydride is used3, and its useful 1i is 3% or less of the total monomers used before polymerization, preferably 03 to 2%, and even if more is used, the contribution to adhesion is small and prevent n+i! There is a risk that it will damage your sexuality.

On the other hand, if the amount used is less than the above amount, only unsatisfactory adhesion will be obtained. In carrying out the present invention, a solution type method is suitable, and the polymerization solvent is a polymerization solvent that can dissolve vinyl chloride units or a vinyl chloride-vinyl vinegar M-vinyl copolymer in an amount of not more than 80% by weight at atmospheric temperature, and Any organic solvent that does not inhibit the reaction even when present in the polymerization system can be used, but esters such as ethyl acetate and butyl acetate are particularly suitable, and the amount used depends on the amount of monomers charged before polymerization. The IHM ratio with the total J fee is 37-72,
Preferably, the polymerization reaction is a first thermal polymerization reaction activated by an initiator at a temperature of 50 to 80'C. The initiator may be one commonly used for this type of polymerization, or an organic initiator such as lauroyl peroxy I. or benzoyl peroxide. Examples include oxides and azo compounds such as azohisisovaleronitrile.
The present invention will be explained below with reference to Examples and Comparative Examples. 4. The method of applying the resin solution obtained in the Examples and Comparative Examples to the surface treatment of cellophane and the resulting treatment. The evaluation method of the film is shown in Table 1.

Example 1 Ethyl acetate was added to a high pressure reactor equipped with a cooling jacket.
0 parts by weight, 21 parts by weight of vinyl acetate bottle, 0.4 Mm part of anhydrous inic acid, 0.1 part of hensoil veroquin l'
After charging 2 parts by weight and 018 parts by weight of lauroyl peroxide and purging the inside of the can with nitrogen, 44 parts by weight of vinyl chloride monomer were introduced, the container was sealed, and stirred.
Subsequently, the temperature was maintained to allow polymerization to proceed. End of heating
After 12.5 hours (t), when 70% of the total amount of the charged material had been converted into polymer, new vinyl chloride 9.1% vinyl chloride was introduced into the polymerization system, and the system was heated for another 7.5 hours. Internal temperature to 65
After keeping the temperature at °C, the reactor was opened and the unreacted vinyl chloride single electrolyte was collected to obtain a vinyl chloride-vinyl acetate copolymer solution with a solid content of 67%. The vinyl chloride star content was 72.5i%, and the average degree of polymerization was 370 based on JIS-6721.

The properties of anti-7M cellophane coated with this copolymer solution were as shown in Table 2 and FIG. 1.

Example 2 In Example 1, the initially charged monomers were changed to 24.5 parts by weight of vinyl acetate single bottle and 4051 parts of vinyl chloride single bottle,
In addition, the procedure was the same as in Example 1, except that the 20-layer vinyl chloride single mouse body introduced into the system during the reaction was charged in two batches at 11.0 hours and 15.4 hours after the start of temperature rise. Manipulated to produce vinyl chloride-hinyl acetate with a solid content of 62% i4↓%.
(Small combined solution i-i!!ta3, vinyl chloride Lli l+
The reaction rate at the time of addition of the body was 65% and 80% based on 7-fold substitution with respect to the prepared body up to that point, and the final reaction rate was 87'.

The vinyl chloride content of the obtained copolymer was 700%, and the average degree of polymerization based on Jls-672+ was 375. Further, the properties of the anti-^d cellophane coated with this copolymer solution were as shown in Table 2 and FIG. 1, and the blocking resistance and heat-sealing strength were sharply dependent on temperature.

Comparative Example 1 In the method of Example 1, vinyl chloride 14 was added during polymerization.
The same procedure as in Example 1 was carried out except that 1M compound was added and the di-holding time was changed to 65° (the total holding time) to 17 hours, and the polymerization reaction rate was 80% and the final solid content was 53. A star percent hinyl chloride-vinyl acetate copolymer was obtained. This copolymer contains 72.5 Mfm% vinyl chloride medium and is JIS-
The average degree of polymerization with K 6721 was 390.

However, using this copolymer liquid, cellophane has 1! /j
Comparing the iM processed product with that of Example 1, the second
As shown in the table and Figure 1, since they are copolymers with the same vinyl chloride content, their blocking resistance is inferior to that of Example 1, and the temperature dependence of heat seal strength is also broad. there were.

Comparative Example 2 In the method of Example 2, 10. The vinyl chloride intermediate was added during the polymerization, and the holding time at 65°C was 16.
A vinyl chloride-vinyl acetate copolymer solution with a solid content of 52.5% by weight was obtained by carrying out the same operation as in Example 2, except that the heating time was changed to 5 hours. The final polymerization core percentage was 795%, and the resulting copolymer contained 70% vinyl chloride units;
The average degree of polymerization according to JIS-6721 is 385,
It was the same as that obtained in Example 2. However, using this copolymer solution, cellophane has an anti-rha effect.
As shown in Table 2 and Figure f41, the treated product has sharper blocking resistance, sharper temperature dependence of heat-nol strength, and even better peak-1-nol strength than in Example 2. 3. Table 1 *1) Solvent composition (10%, 10%, 10% ethyl chloride, 1%
:butyl acid 65/20/'15 Table 2 As is clear from Table 2, Example 1.2 in which Φ11-do-C hinyl chloride monomouse was added is different from Comparative Example 1 in which no additional operation was performed. Compared to .2, even though they have the same composition, the anti-flocking temperature is sC, Ht). This is clearly due to the addition of one vinyl chloride substance during polymerization, resulting in vinyl acetate.
Jl has the effect of suppressing the generation of Rimmer.

[Brief explanation of drawings]

FIG. 1 is a graph comparing the heat seal strengths of Examples 1 and 2 of the present application and Comparative Examples 1 and 2. Patent applicant Makoto Asano, patent attorney, Kanebuchi Chemical Industry Co., Ltd.

Claims (3)

[Claims] (1) Vinyl chloride, vinyl acetate, and the like in the presence of a solvent at 3% rJ"4 and 1jJ,
In the ternary copolymerization of β-unsaturated cycarphonoic acid or its anhydride, after the polymerization reaction rate of the monomer charged before polymerization reaches 50 tons, the polymerization side charge 1p 1,1
: IE that is characterized by adding 10 to 30 tons of hinyl chloride to the polymerized yarn continuously or in parts.
combination d1. . (2) The use of hinyl chloride and hinyl acid acetate at the beginning of the first batch.1) 1"Preparation single excipient total amount 0)97 tonne hare%
or more, and the ratio of both A is 55-70:45-30
The polymerization method according to claim 1. (3) It is a solvent that is present in the 11i polymerization system or dissolves the covalent polymer that is formed, and [1-) The total amount of polymerized mfl-containing tJ1 is comparable to that of dj. 37 to 7/.3゛C.