JPS6059253B2 - Manufacturing method for vinyl chloride resin molded products - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing a vinyl chloride resin molded article, and in particular, by modifying the surface properties of the molded article, plasticizers and other additives inside the molded article can be removed. This invention relates to a method for sustainably preventing the phenomenon of oozing and migrating onto the surface of a molded product over time.

When vinyl chloride resin is not mixed with a plasticizer, it gives a hard steel-like molded product, but since the hardness can be adjusted by adding a plasticizer such as phthalate, it is difficult to make a hard molded product. It is widely used not only for products but also for so-called soft molded products.

In this molding process, in addition to plasticizers, stabilizers, lubricants, antioxidants, chelators, non-drip agents, Various additives and compounding agents such as ultraviolet absorbers and fillers are used for films, sheets, synthetic leather, tubes, hoses,
Medical equipment, as various products such as bags, packing, covering materials, etc.
It is widely applied to food packaging materials, wire covering materials, agricultural materials, construction materials, etc. However, there is a phenomenon in such vinyl chloride resin molded products that the plasticizers and other additives contained in them migrate to the molded product surface and ooze out over time, which can cause contamination of the appearance and ooze out. It is considered to have major drawbacks in terms of deterioration, toxicity (hygienic safety), durability, etc., and there is a problem that it is particularly limited in its application for medical and food purposes.

As a countermeasure to these problems, it is possible to treat the surface of the molded product with ionizing radiation, ultraviolet rays, or chemical means, but such methods can improve heat resistance, solvent resistance, etc., and improve hydrophilicity. Although antistatic properties and printability are achieved to some extent, it is not only impossible to prevent the oozing out of plasticizers, etc., but also disadvantageous in that the inherent properties of vinyl chloride resin are diminished.

In other words, since the energy of ionizing radiation treatment is too strong, it acts not only on the surface of the molded product but also to some extent inside the molded product, causing intermolecular crosslinking reactions, which greatly deteriorates the original properties of vinyl chloride resin. In addition, UV treatment has the problem of discoloration due to decomposition and deterioration of the surface of the molded product, and furthermore, when using chemical means, there are problems with erosion of the molded product and problems with the adhesion and durability of the treatment agent. . On the other hand, attempts have been made to modify the surface of plastic molded products such as polyethylene by subjecting them to low-temperature plasma treatment. Although an effect of preventing oozing is observed, if it is exposed outdoors for a long period of time, the preventive effect disappears over time, resulting in poor weather resistance and durability.

As a result of intensive research in order to solve these problems, the present inventors found that the general formula (wherein R1 is a hydrogen atom, -CH2C
Represents H2OH or -COOH, n is 5 to 150
It is.

) When a vinyl chloride resin composition prepared by blending polybutadiene and/or modified polybutadiene shown in The present invention has been completed by discovering that the crosslinking reaction can be favorably promoted, thereby preventing additive components such as plasticizers from oozing out onto the surface of the molded product over a long period of time.
The present invention will be explained in detail below.

In the present invention, it is necessary to blend polybutadiene and/or modified polybutadiene shown in the formula below with the vinyl chloride resin. It may be produced by a polymerization method such as ping polymerization, and includes a butadiene homopolymer without a functional group at the end group, a polybutadiene glycol having a hydroxyl group at both ends, or a polybutadiene glycol having a carboxyl group at both ends. Examples include polybutadienecarpotsic acid and the like.

Modified polybutadiene refers to the various polybutadienes listed above that have been modified with other compounds, such as polybutadiene with maleic anhydride added to the tertiary carbon position, or polybutadiene with maleic anhydride added to the tertiary carbon position, or polybutadiene with a double bond in the molecule. An example is one in which a portion is epoxidized.

There is no particular restriction on the molecular weight of the polybutadiene or modified polybutadiene represented by formula (4), but workability,
A liquid prepolymer having a pour point of 30° C. or lower is preferable from the viewpoint of processability and the like.

The blending ratio of the polybutadiene and/or modified polybutadiene represented by formula (4) should be 0.1 to 5 parts by volume (preferably 1 to 3 parts by volume) per 10 parts by volume of the vinyl chloride resin. Desirably, if this amount is too small, the formation of the surface crosslinked layer by the above-mentioned low-temperature plasma treatment will be insufficient, and if it is too large, it will not be possible to obtain a molded product with the original performance of vinyl chloride resin. .

The vinyl chloride resin composition used in the method of the present invention is
In addition to containing the polybutadiene and/or modified polybutadiene represented by the above formula (4) as an essential component, it may also contain various additives and compounding agents that are normally blended with vinyl chloride resins.

For example, it is desirable to add various antioxidants for the purpose of improving stability and durability during molding and over time. Propionate, 2,2″-thiodiethylbis[3-(3,5-
diterciabutyl-4-hydroxyphenyl)propionate], P,p''-dioctyldiphenylamine,
3,7-ditertiaryoctylphenotidine, N,N''
-hexamethylene bis(3,5-ditertyabutyl-4-hydroxycyanamide) and the like are exemplified.

The vinyl chloride resin molded article targeted by the method of the present invention may be any one manufactured from polyvinyl chloride or a copolymer mainly composed of vinyl chloride, and in this case, it may be copolymerized with vinyl chloride. Comonomers include vinyl esters, vinyl ethers, acrylic acid or methacrylic acid and their esters, maleic acid or fumaric acid or their esters and maleic anhydride, aromatic vinyl compounds, vinylidene halides, acrylonitrile or methacrylonitrile, ethylene, propylene. Examples include olefins such as

These vinyl chloride resins are not limited to one type, but may be used as a blend of two or more types, and other synthetic resins may be blended for the purpose of improving the mechanical strength etc. of the molded product. Examples of synthetic resins include ethylene-vinyl acetate copolymer, acrylonitrile-butadiene copolymer, styrene-acrylonitrile copolymer, and methyl methacrylate.
Examples include styrene-butadiene copolymer, acrylonitrile-styrene-butadiene copolymer, polyamide resin, prolactam polymer, epoxy-modified polyol, and organopolysiloxane. Note that various compounding agents and additives may be added to the vinyl chloride resin as necessary.
For example, plasticizers used to adjust the flexibility and hardness of molded products include phthalic acid esters such as dioctyl phthalate, dibutyl phthalate, and butylbenzyl phthalate, and aliphatic esters such as dioctyl adipate and dibutyl sebacate. Basic acid esters, pentaerythritol esters, glycol esters such as diethylene glycol dibenzoate, fatty acid esters such as methyl acetyl ricinoleate, phosphate esters such as tricresyl phosphate and triphenyl phosphate, epoxidized soybean oil, epoxidized linseed oil, etc. Plasticizers with various structures such as epoxidized oil, citric acid esters such as acetyl tributyl citrate and acetyl trioctyl citrate, trialkyl trimellitate, tetra n-octyl pyromellitate, polypropylene adipate, and other polyesters are used. Illustrated.

In addition, as additives used to improve properties such as lubricity and stability, metal salts of carboxylic acids such as calcium stearate, zinc stearate, lead stearate, barium stearate, and cadmium stearate, tribasic Lead sulfate, dibasic lead phosphite, dibutyltin dilaurate,
Organotin compounds such as di-n-octyltin malate and di-n-octyltin mercaptite, esters such as butyl stearate, fatty acid amides such as ethylene bisstearamide, higher fatty acids and their esters, or polynylene wax. Examples include Tsukusu et al.

Other additives used in molding vinyl chloride resins include fillers, heat resistance improvers, ultraviolet absorbers, antistatic agents, anti-drop agents, pigments, dyes, crosslinking aids, and the like. The method for obtaining a vinyl chloride resin molded product may be any conventional molding method used for molding vinyl chloride resin, such as extrusion molding, injection molding, calendar molding, inflation molding, or compression molding, depending on the type of molded product. , there are no particular restrictions on the shape. Next, the vinyl chloride resin molded product was 10
It is used for low-temperature plasma processing of inorganic gases of less than Torr.

As a treatment method for inorganic gas using low-temperature plasma, 10
The molded article may be treated with a low-temperature plasma of an inorganic gas under a pressure of less than Torr, and the plasma generation conditions at this time may be, for example, several KHz to several hundred MHz between the electrodes.
It is only necessary to apply a high frequency power of z, and sufficient results can be obtained whether the discharge is a polar discharge or an electrodeless discharge. The plasma processing time varies depending on the applied voltage, but generally a few seconds to several tens of minutes is sufficient. In addition, there are various methods for plasma processing other than the above.For example, low frequency, microwave, direct current, etc. can be used as the discharge frequency band, and the electrodes can be external electrodes, internal electrodes, coil type, etc. Either capacitive coupling or inductive coupling is suitable.

However, whatever method is used, it is necessary to prevent the surface of the material from deteriorating due to discharge heat. Inorganic gases include helium, neon, argon, nitrogen, oxygen, nitrous oxide, nitrogen dioxide, carbon monoxide, carbon dioxide, hydrogen,
Examples include chlorine, halides such as hydrogen chloride, bromine cyanide, and tin bromide, and sulfides such as sulfite gas and hydrogen sulfide, and these gases may be used alone or in combination. The desired plasma can be generated satisfactorily by setting the gas pressure of these gases in the plasma generator to 1 torr or less, particularly preferably from 0.001 to 1 torr. In the molded product obtained by low-temperature plasma treatment by the method of the present invention, the phenomenon in which internal additives such as plasticizers ooze out onto the molded product surface is completely suppressed, and the surface crosslinked layer formed on the surface has flexibility. In addition to having excellent characteristics in terms of durability and stability, the present invention also makes it possible to shorten the processing time due to its plasma processing acceleration effect, and therefore provides a wide range of advantages in the plasma processing process. It is.

A further advantage of the method of the present invention is that the formed surface crosslinked layer has excellent durability, and even when used outdoors for a long period of time, the crosslinked layer does not break down and maintains its full functionality. There are some points that have remarkable properties. The plasma-treated molded product has excellent surface properties in terms of water resistance, stain resistance, oil resistance, chemical resistance, hydrophilicity, and the like. Next, specific examples will be given.

Example 1 Vinyl chloride resin (trade name manufactured by Shin-Etsu Chemical Co., Ltd. to TK-130)
10 weight parts, DOP 5 weight parts, epoxidized soybean oil (oxirane oxygen 7. heel weight %) 5 weight parts, calcium stearate 1. A compound consisting of 1.0 parts by weight of zinc stearate was molded into a sheet having a thickness of 0.3 wgn.

This is designated as sample-1. Vinyl chloride resin (TK-130
Shin-Etsu Chemical Co., Ltd. product name) 10 weighing parts, DOP5 weighing parts,
Epoxidized polybutadiene (oxirane oxygen 8% by weight,
Viscosity 25,000 centistokes, 25°C) 5 parts by weight,
Calcium stearate 1J parts by weight, zinc stearate 1. A compound consisting of a nominal weight part was molded to create sheets with a thickness of 0.3.

This will be referred to as sample-2. Sample-1 and Sample-2 were each set in a plasma generator, and the pressure was increased to 0.03 torr while passing a mixed gas of carbon monoxide and argon (mixture ratio CO/Ar''=1/9) under reduced pressure. Adjust and hold at 100KH
The samples were processed for the time (seconds) shown in Table 1 by applying a high frequency power of 15 KW.

The treatment time and plasticizer elution prevention effect of Sample-1 and Sample-2 were investigated, and the results were as shown in Table 1.

The plasticizer elution prevention effect was measured by the amount of n-hexane extracted. Method for measuring the amount of n-hexane extracted: A sample sheet was set at the bottom of a 100 ml cylindrical extraction container, the surface of this 26 cf1 was brought into contact with 50 ml of n-hexane, and the mixture was shaken in a water bath at 3 rC for 2 hours. The amount (M9) of plasticizer (DOP) extracted into n-hexane was quantitatively analyzed by gas chromatography.

Example 2 100 parts by weight of vinyl chloride resin (TK-1300), ]D
OP5 weighing part, epoxidized soybean oil (oxirane oxygen 7.
5 parts by weight), 1.5 parts by weight of calcium stearate, 1.5 parts by weight of zinc stearate, 5 parts by weight of bisphenol AO. The compound consisting of the heel portion is molded to a thickness of 0.3
I created a fabric sheet.

This is designated as Sample 2-3. Vinyl chloride resin (TK-13
00) 100 parts by weight, 5 parts by weight of DOP, 5 parts by weight of epoxidized polybutadiene (oxirane oxygen 7.0% by weight), 1.5 parts by weight of calcium stearate, 1.5 parts by weight of zinc stearate, 1 part by weight of bisphenol AO. The compound consisting of the weight part was molded to create a sheet with a thickness of 0.3wn.

This is designated as sample-4. Sample-3 and Sample-4 were each set in a plasma generator, and the pressure was increased to 0.1 torr while passing a mixed gas of carbon monoxide and argon (mixture ratio CO/.Ar = 1/1) under reduced pressure. Adjust and hold to 13.5
5 by applying high frequency power of 6MHz 13KW.
Processed for seconds.

For Sample-3 and Sample-4, the initial n-hexane extraction amount and the n-hexane extraction amount (Mg) after forced deterioration were measured using a weather meter, and the results shown in Table 2 were obtained.

Forced deterioration test method using weathermeter: Standard Sunshine Weatherometer, WESUN. Using HC type (manufactured by Toyo Rika Co., Ltd.) for 10 (t) or 50yi! Forced deterioration during If.

Example 3 100 parts by weight of vinyl chloride resin (TK-1300), DO
A blend consisting of 1.5 parts by weight of P5, 1.5 parts by weight of calcium stearate, and 1.5 parts by weight of zinc stearate was molded into a sheet having a thickness of 0.3 w.

This is designated as sample-5.

100 parts by weight of vinyl chloride resin (TK-1300), DO
A mixture consisting of P5 mass part, 1 part of polybutadiene (B-3000: Nippon Soda Co., Ltd. trade name, pour point 1γC), 1.5 parts by weight of calcium stearate, and 1.5 parts by weight of zinc stearate was molded. A sheet having a thickness of 0.3 Tfgn was prepared.

This is designated as sample-6. Sample-5 and Sample-6 were each set in a plasma generator, and the pressure was adjusted and maintained at 0.05 torr while passing carbon monoxide gas under reduced pressure.
The treatment was performed by applying high frequency power of 5 KW (0 KHz).

The treatment time and plasticizer elution prevention effect of Sample-5 and Sample-6 were investigated, and the results were as shown in Table 3.

Furthermore, the amount of n-hexane extracted after forced deterioration was measured using a weather meter for those treated for 4 seconds, and the results were as shown in Table 4.

Example 4 100 parts by weight of vinyl chloride resin (TK-1300), DO
A blend consisting of P5 heel weight, 1.5 parts by weight of calcium stearate, and 1.5 parts by weight of zinc stearate was molded to form a sheet with a thickness of 0.37Q.

This is designated as sample-7.

100 parts by weight of vinyl chloride resin (TK-1300), DO
P5 tumor area, maleated polybutadiene (acid value 110)
7 parts by weight of calcium stearate, 1.5 parts by weight of calcium stearate, and 1.5 parts by weight of zinc stearate was molded into a sheet with a thickness of 0.3 m.

This is designated as sample-8. Sample-7 and Sample-8 were each set in a plasma generator, and the pressure was adjusted and maintained at 0.04 torr while passing argon gas under reduced pressure.
The treatment was performed by applying high frequency power of 5 KW (kHz).

The processing time and plasticizer elution prevention effect of Sample-7 and Sample-8 were investigated, and the results were as shown in Table 5.

Claims (1)

[Claims] 1 Polybutadiene represented by the general formula ▲ Numerical formulas, chemical formulas, tables, etc. ▼ (In the formula, R^1 represents a hydrogen atom, -CH_2CH_2OH or -COOH, and n is 5 to 150.) and/or modified polybutadiene is molded, and the molded product is then treated with low-temperature plasma of an inorganic gas of 10 torr or less. Method. 2 The blending ratio of polybutadiene and/or modified polybutadiene is 10% of vinyl chloride resin.
2. The method according to claim 1, wherein the amount is 0.1 to 50 parts by weight per 0 parts by weight.