JPS63125507A - Production of polymer - Google Patents

Abstract

PURPOSE:To obtain a polymer excellent in melt flow upon heating and adhesion to a polyester fiber or the like, by suspension-polymerizing a vinyl chloride monomer mixture in the presence of a specified polyester in an aqueous medium containing a suspending agent. CONSTITUTION:A monomer mixture comprising 40-100wt% vinyl chloride monomer and 60-0wt% other monomers (e.g., vinylidene chloride) is suspension- polymerized in an aqueous medium containing 0.2-2.0pts.wt., per 100pts.wt. total monomer, suspending agent (e.g., partially saponified PVA) and having a surface tension <=50dyn/cm in the presence of 2-100pts.wt. per 100pts.wt. total monomer, polyester having a number-average MW of 2,000-50,000 and being in the form of a cylinder of an outside diameter of 2-3mm and a length of 2-3mm and a polymerization initiator (e.g., benzoyl peroxide).

Description

Detailed Description of the Invention (a) Purpose of the Invention [Field of Industrial Application] The present invention is a hot-melt adhesive that has excellent melt flowability when heated and has good adhesion to cotton, polyester fibers, polypropylene fibers, etc. This paper relates to a method for producing a chlorine-containing polymer that can be used as an agent. In particular, since the polymer can be obtained as enlarged particles, it is possible to industrially produce a powdered polymer that can be bonded between felt layers. It can be manufactured advantageously.

[Conventional technology and its problems]

A copolymer consisting of a vinyl chloride monomer unit as a main unit and a vinylidene chloride monomer unit or a vinyl acetate monomer unit is inexpensive and has excellent flame retardancy, so it can be used as a hot-melt type adhesive for the shaft part. used as an agent. However, these copolymers have poor melt flowability at temperatures below 180° C., and have low adhesion ability to fibers or nonwoven fabrics, especially synthetic fibers or nonwoven fabrics.

Furthermore, when powdered hot melt adhesive is used as a binder between felt layers, in order for the adhesive to function effectively, it is necessary that as much of the adhesive powder sprinkled on the felt as possible be applied to the fibers near the surface of the felt layer. For this purpose, it is desirable that the adhesive powder has a particle size that hardly passes through the 120-mesh joint and almost passes through the 20-mesh joint. However, it is not possible to process a powdered adhesive with such a coarse particle size and a relatively narrow particle size distribution through a mechanical pulverization process or from a powdered adhesive with a wide particle size distribution without passing it through a multiple sieving process. It has been difficult to obtain this in the past.

As a countermeasure to this problem, attempts have been made to obtain copolymers such as vinyl chloride-vinylidene chloride or vinyl chloride-vinyl acetate through suspension polymerization, but the particle size of the resulting polymers is still generally too small. Alternatively, even if a coarse particle polymer is obtained, fine particles are mixed into the polymer, and the present situation is that a powder adhesive suitable for use in the above-mentioned applications cannot be obtained.

(B) Structure of the Invention [Means for Solving the Problems] The present inventors have completed the present invention as a result of intensive study on the above-mentioned problems.

That is, in the present invention, a vinyl chloride monomer or a monomer mixture mainly composed of vinyl chloride monomer is mixed with 0.2 to 2.0 parts by weight of a suspending agent per 100 parts by weight of the total monomers. This is a method for producing a polymer, which is characterized by carrying out suspension polymerization in an aqueous medium containing a polyester having a surface tension of 5 Q dyne/α or less in the presence of a polyester having a number average molecular weight of 2,000 to 5 oooo.

The present invention will be explained in detail below.

The monomer that can be used in the present invention is a vinyl chloride monomer or a monomer mixture mainly consisting of a vinyl chloride monomer.

When a monomer other than vinyl chloride monomer is used, the amount of such monomer used is preferably 40% by weight or less, based on 100% by weight of all monomers.

If it exceeds 40% by weight, the vinyl chloride polymer loses its characteristic flame retardancy and versatility due to its low price, and furthermore, the compatibility with the polyester used in the present invention decreases, so it is preferable. do not have.

Monomers other than vinyl chloride monomers that can be suitably used in the present invention include vinylitine chloride, vinyl ester, vinyl ether, acrylic ester, vinyl ketone, allyl chloride, methallyl chloride, acrylic acid, and hydroxyl. Examples include ethyl acrylate, maleic anhydride, N-acrylamide, and glycidyl methacrylate.

Among the above monomers, vinylene chloride, vinyl ester, vinyl ether, acrylic ester, vinyl ketone, allyl chloride, and methallyl chloride are used for the purpose of improving the melt fluidity of the obtained polymer. Monomers mentioned and used for the purpose of improving adhesive ability include acrylic acid, hydroxyethyl acrylate, maleic anhydride, N-acrylamide or glycidyl methacrylate.

Furthermore, a monomer mixture mainly composed of vinyl chloride monomer obtained by using vinylidene chloride and allyl chloride or methallyl chloride has high melt fluidity and heat resistance when used in the method of the present invention. This is particularly preferred in that a polymer with suppressed degradability can be obtained.

The amount of suspending agent used in the present invention is 100% of the total monomer.
It is necessary that the amount is 0.2 to 2.0 parts by weight. If the amount is less than 0.2 parts by weight, surprisingly, fine polymer particles tend to be produced, which is unsuitable, unlike the tendency of ordinary suspension polymerization methods. On the other hand, if it exceeds 2.0 parts by weight, the usual tendency for suspension polymerization or emulsion polymerization will be observed, and the amount of fine polymer particles produced will increase rapidly, which is unsuitable. A more preferable amount of suspending agent used is 0.5 to 1.5 parts by weight.

Examples of suspending agents that can be used include partially saponified polyvinyl alcohol, cellulose derivatives, copolymers of ethylene oxide and propylene oxide, and copolymers of vinyl acetate and maleic acid, which may be used alone or in combination. Two or more types can be used in combination.

The aqueous medium used for suspension polymerization in the present invention contains the above-mentioned suspending agent in a specific amount and has a surface tension of 50 dyne.
/cR or less.

When it exceeds 50 dyne/2, it is difficult to obtain large polymer particles with uniform particle size. The reason for this is that when the surface tension of the aqueous medium is high, it is impossible to entrain air bubbles into the polymerization solution under stirring, which makes it difficult to generate enlarged particles with uniform particle size based on air bubbles. it is conceivable that.

Furthermore, an important feature of the present invention is that by reducing the surface tension of the aqueous medium to 50 dyne/cIL or less before the start of polymerization, even if fine particles are generated17, the slurry can be washed and the solid concentration can be made uniform after polymerization. In the process of adding water and stirring in a tank of slurry for the purpose, fine particles containing air bubbles migrate to the upper layer, while polymer particles to be used as products are continuously extracted from the bottom of the tank of slurry. In this state, if the particles are run through a continuous centrifuge, useful enlarged particles can be directly collected.

However, the surface tension of a more preferable aqueous medium is 40 dyne.
/cm or less.

The surface tension of the aqueous medium in the present invention refers to the surface tension of the aqueous medium to which the suspending agent and/or the water-soluble surfactant described below are added. I
Surface tension at 25° C. measured by Dunoy's method using NTERFACI® TENSIaMgrER).

As a method of adjusting the surface tension of the aqueous medium, there is a method of using a relatively large amount of a suspending agent, but a method of adding a water-soluble surfactant having excellent emulsifying properties is preferable.

Examples of the water-soluble surfactants include fatty acid or rosin acid soaps, anionic surfactants such as alkyl sulfate salts or alkyl sulfonate salts, polyoxyethylene fatty acid esters, polyoxyethylene higher alcohol ethers, and polyoxyethylene polyalcohol ethers. Examples include nonionic surfactants such as alcohol esters. Examples of the surfactant having a better ability to lower surface tension include fluorine-based surfactants having a similar structure to the above-mentioned surfactants. The amount of these surfactants used is preferably 0.001 to 1 part by weight when the amount of all monomers used is 100 parts by weight.

Polyesters that can be used in the present invention include:
Number average molecular weight is 2000-5ooo.

However, there are no particular restrictions on the constituent units of the polyester.

When a polyester having a number average molecular weight of less than 2,000 is used, the resulting polymer has a low adhesion ability and becomes fine particles, which is not suitable.

On the other hand, if it exceeds 5oooo, crystallinity increases, solubility in vinyl chloride monomer becomes poor, and suspension polymerization becomes difficult, making it unsuitable. A more preferable number average molecular weight range is 6000 to 200.00.

In addition, the number average molecular weight of the polyester in the present invention is
This is the molecular weight in terms of polystyrene determined by gel permeation chromatography, and the measurement conditions are as follows.

Equipment: High performance liquid chromatography (e.g. Toyo Soda Kogyo product name HLC-802UR) Column: Polystyrene glue (e.g. Toyo Soda Kogyo product name G4000 H8 and G3000H8) Elution solvent: Tetrahydrofuran Outflow rate: i, Od/ Column temperature: 40°C Detector: RI detector Examples of polyesters used in the present invention include:
Dicarboxylic acids such as terephthalic acid, isophthalic acid, adipic acid, sepathic acid or maleic acid and ethylene glycol, 7'.

There are polyesters with a number average molecular weight of 2,000 to 50,000 obtained by a polycondensation reaction with a compound containing two or more hydroxyl groups in one molecule, such as helene glycol, phthylene gelylcol, trimethylolpropane, or pentaerythritol. For example, commercially available PBS-MDH
%PE5-110L, PES-320 and PES-33
0 (all manufactured by Toagosei Kagaku Kogyo ■).

The amount of the above polyester to be used is not particularly limited as long as it is used in a certain amount or more, but if a significant effect on adhesive ability or increase in average adhesiveness is expected, it should be added to 100 parts by weight of the total monomer. It is preferable to use 2 parts by weight or more. On the other hand, if 100 M parts or more is used, the viscosity of the polymerization solution tends to become too high, making it difficult to carry out smooth polymerization.
It is preferable to avoid it.

In the present invention, the polyester is dissolved in an oil droplet layer formed by vinyl chloride monomer or a monomer mixture mainly composed of vinyl chloride monomer immediately before monomers start polymerization in suspension polymerization. It is presumed that some of the polyester fine particles are transferred to the core oil droplet layer in a dispersed state. When polymerization of monomers starts in the oil droplet layer containing such a polyester, the polymerization proceeds with the polyester as the core, resulting in the production of a polymer with enlarged particles.

Therefore, as the polyester used in the present invention, an excessively large solid substance is not very desirable because it takes a long time to dissolve into the oil droplet layer, but a solid substance having an outer diameter of 2 to 3 IIi and a length of 2 to 3 fl is not very desirable. There is no problem with this beret.

Compounds that can be used as polymerization initiators for suspension polymerization in the present invention include oil-soluble radical-generating compounds that are generally used as polymerization initiators for suspension polymerization, and specific examples include benzoyl peroxide, Examples include lauroyl peroxide, di-2-ethylhexyl peroxydicarbonate, and α,α゛-dimethylvaleronitrile.

The present invention will be explained in more detail below with reference to Examples and Comparative Examples.

All parts and parts on each side refer to parts and percent by weight, respectively.

In addition, each characteristic of the polymer obtained on each side was measured by the following method.

(2) Particle size distribution The distribution was determined by the water sieve method using 20, 60.80 and 120 mesh sieves.

■ Apparent specific gravity It was determined according to JIS K 6721.

■ 180° Peel Adhesion Strength Spread polymer powder uniformly at 20 fr/yj on felt made of a blend of polyester and cotton (weight ratio <65,755), layer the same felt on top, and heat at 150°C.
x O, 5 kg/dlx A test piece obtained by press bonding for 15 seconds was measured for 180° peel strength at 25°C.

Example 1 500! In an autoclave, add 9 to 260% pure water, GH-23 (partially saponified polyvinyl alcohol, manufactured by Nippon Gosei Kagaku Kogyo) 7501r as a suspending agent, and Epan 485 (block copolymer of ethylene oxide and propylene oxide, manufactured by Dai-ichi Kogyo). (Manufactured by Pharmaceutical ■) 7505Lr and Megafa, RiF-
120 (anionic fluorine-containing surfactant, manufactured by Inu Nippon Ink Kagaku Kogyo ■) 15pr was added and stirred to obtain a uniform aqueous solution. A small portion of the aqueous solution was taken out and its surface tension was measured, and the result was 30 dyne/cx.

Next, 120 yen of vinyl chloride, 30 yen of vinylidene chloride, 15 kg of PES-11OL (polyester with a number average molecular weight of 6,800), and 450 yen of di-2-ethylhexyl peroxydicarbonate as a radical-generating polymerization initiator were placed in the autoclave. After the addition, suspension polymerization was carried out at 60° C. for 12 hours while stirring at 24 rpm.

The centrifugal dehydration layer was dried to obtain a powdered polymer with a polymerization conversion rate of 78% by weight. Table 1 shows the measurement results of the surface tension of the aqueous solution in the polymerization system before the start of polymerization and the results of the physical property evaluation test of the obtained polymer.

Examples 2 to 10 and Comparative Examples 1 to 4 The types and amounts of monomers, polyesters, suspending agents, or other surfactants in Example 1 were changed as shown in Table 1, and Other polymerization conditions were the same as in Example 1 to carry out the polymerization.

The results are shown in Table 1 as Examples 2 to 10 and Comparative Examples 1 to 4.

(C) Effects of the Invention According to the present invention, it is possible to easily produce a vinyl chloride polymer having a large particle size and suitable as a hot-melt adhesive between felt layers made of synthetic fibers or the like.

Claims (1)

[Claims] 1. Add vinyl chloride monomer or a monomer mixture mainly composed of vinyl chloride monomer to 0.2 to 100 parts by weight of the total monomer.
Contains 2.0 parts by weight of suspending agent and has a surface tension of 50 d
In an aqueous medium of yne/cm or less, the number average molecular weight is 20
A method for producing a polymer, which comprises carrying out suspension polymerization in the presence of a polyester having a molecular weight of 0.00 to 50,000.