JPH101584A - Rigid vinyl chloride resin sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a rigid vinyl chloride resin sheet improved in the retention of heat resistance and initial discoloration, excellent in heat stability, capable of coping with the enlargement and speed-up of processing machines, and usable for packaging materials excellent in transparency, processability and sanitation. SOLUTION: This sheet is made from 100 pts.wt. vinyl chloride resin, 0.01-1 pt.wt. calcium compound, 0.01-1 pt.wt. zinc compound, 0.01-5 pt.wt. epoxidized vegetable oil, 0.01-1 pt.wt. β-diketone compound, and 0.05-0.5 pt.wt. ester compound. The average-degree of polymerization of the vinyl chloride resin is 600-900, and the ester compound is a mixed ester of pentaerythritol with a 11-20 C higher fatty acid and a 4-6 C saturated dibasic acid.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rigid vinyl chloride sheet used for packaging materials such as foods and medicines after being processed into various predetermined shapes. More specifically, the present invention relates to a rigid vinyl chloride sheet for a packaging material which is excellent in thermal stability, corresponds to an increase in the size and speed of a processing machine, and is excellent in transparency, processability and hygiene.

[0002]

2. Description of the Related Art Halogen-containing resins such as vinyl chloride are
During the thermoforming process, thermal decomposition mainly due to dehydrohalogenation is apt to occur, which causes deterioration of mechanical properties and color tone of the processed product, resulting in a significant disadvantage. In order to avoid such disadvantages, it is necessary to add one or several kinds of heat stabilizers to the synthetic resin to suppress deterioration in the processing step. For such a purpose, a heat stabilizer obtained by adding an organic phosphate, a phenolic compound, or an epoxy compound to a combination of metal compounds such as lead, cadmium, barium, and zinc has been used. But,
Metals such as lead, cadmium and barium are highly toxic, and various problems arise in the treatment of waste after use of processed products of vinyl chloride resin using them.

Accordingly, a heat stabilizer comprising an organic phosphate, a phenolic compound and an epoxy compound added to a combination of a calcium / zinc metal compound which does not use a lead, cadmium and barium metal compound stabilizer is used. The lead, cadmium, and barium-based metals have been used for thermal decomposition due to dehydrohalogenation, and the durability of heat resistance and the prevention of initial coloring (the phenomenon of initial coloring in the heat history during processing). There was a major drawback in that it was inferior to stabilizers containing compound stabilizers. In order to solve these drawbacks, β-diketone compounds represented by the following general formula have been used as calcium / zinc-based metal compound stabilizers as heat stabilizers, in particular, as an initial coloring inhibitor, and have been effective ( JP-B-52-47948). R-CO-CHX-CO-R (wherein X represents a hydrogen atom or 1-2 alkyl groups, and R represents an alkyl group or an aryl group)

However, in recent years, the size of calendar equipment has been increased,
Due to the high speed, only the combination of calcium / zinc based metal compound stabilizers and other stabilizing aids such as organic phosphoric esters, phenolic compounds, epoxy compounds, diketone compounds, etc. is insufficient in thermal stability and heat resistance. In addition, the thermal disintegration of vinyl chloride resin is mixed in the product due to poor initial coloration prevention properties, and the color tone and physical properties of the product are deteriorated, resulting in a major obstacle to production. Prescription rigid vinyl chloride sheets have been desired. On the other hand, the zinc compound has the effect of less initial coloring by effectively capturing the hydrogen chloride generated by the heat history of the vinyl chloride resin, but the zinc chloride generated here becomes a catalyst and causes further dehydrochlorination reaction,
There was a problem that rapid thermal decomposition called a so-called zinc burning phenomenon occurred, and blackening and decomposition occurred within a short period of time, resulting in poor heat resistance.

The problem of zinc burning is represented by polyhydric alcohols such as mannitol, sorbitol, pentaerythritol and dipentaerythritol, and inorganic salts such as oxides and hydroxides such as hydrotalcite, zeolite, calcium and magnesium. The problem is solved by adding a costabilizer. However, the polyhydric alcohol substance has a relatively short stabilization time, and tends to inhibit the initial coloring prevention effect by incorporating a zinc compound which is extremely effective in preventing the initial coloring into its structure. Among them, pentaerythritol and dipentaerythritol are relatively effective, but have a drawback that production equipment such as a calender roll and a cooling roll is remarkably soiled due to their sublimability, and cannot be mass-produced. Further, co-stabilizers represented by inorganic salts tend to cloud the product, and there are various restrictions such as restrictions on the amount of addition, and no satisfactory co-stabilizers existed.

[0006] The vinyl chloride resin sheet is produced by calender rolling, and higher fatty acid compounds such as stearic acid and lauric acid are mainly used as a lubricant to be added. However, since the higher fatty acid compound is an acid-based lubricant having a carboxylic acid group, the carboxylic acid reacts with the metal compound as a stabilizer and is colored red, or impairs the effect of capturing hydrogen chloride and deteriorates the initial coloring. There were drawbacks.

[0007]

DISCLOSURE OF THE INVENTION The present invention has been made as a result of intensive studies in order to solve the conventional problems as described above. A rigid vinyl chloride sheet with excellent thermal stability, which is compatible with large-scale and high-speed processing and production machines, and offers a rigid polyvinyl chloride sheet for packaging materials with excellent transparency, processability, and hygiene. Is to do.

[0008]

SUMMARY OF THE INVENTION The present invention relates to a calcium compound having a concentration of from 0.01 to 100 parts by weight of a vinyl chloride resin.
1 part by weight, zinc compound 0.01 to 1 part by weight, epoxidized vegetable oil 0.1 to 5 parts by weight, β-diketone compound 0.0
A hard vinyl chloride sheet comprising a composition to which 1 to 1 part by weight and 0.05 to 0.5 part by weight of an ester compound are added. More preferably, the average degree of polymerization of the vinyl chloride resin is 600 to 900. The ester compound is a mixed ester of pentaerythritol, a higher fatty acid having 11 to 20 carbon atoms and a saturated dibasic acid having 4 to 6 carbon atoms, and has a softening temperature measured by a softening temperature test according to JIS K6734. 50 to 80 ° C., and the sheet thickness is 0.
It is a hard vinyl chloride sheet measuring from 0.5 to 1.0 mm.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in further detail. The vinyl chloride resin blended as a main component in the rigid vinyl chloride sheet of the present invention has an average degree of polymerization of 600 to 600.
900. If this is over 900,
If no plasticizer is added, the processability is poor. Therefore, if a large amount of the plasticizer is added, the softening temperature is lowered. On the other hand,
When the thickness is less than 600, the heat resistance of the formed sheet is reduced, and problems such as re-forming after forming into a predetermined shape are caused. In addition, workability such as softening of the film and reduced cutability is reduced. . Examples of the polyvinyl chloride resin include a vinyl chloride homopolymer, a copolymer of a vinyl-based monomer copolymerizable with vinyl chloride, each containing 80% or more of vinyl chloride, and vinyl chloride and various polymers or polyvinyl chloride. Includes graft polymers of vinyl chloride and vinyl monomers, post-chlorinated vinyl chloride polymers, and mixtures thereof, which are produced by any method such as bulk polymerization, suspension polymerization, emulsion polymerization, and solution polymerization. Also included are those that have been done.

[0010] Vinyl monomers used for copolymerization or graft polymerization include olefins such as ethylene and propylene, halogenated olefins other than vinyl chloride such as vinylidene chloride and vinylyl fluoride, vinyl acetate, and vinyl laurate. Such as vinyl esters, 2-ethylhexyl vinyl ether, alkyl vinyl ethers such as dodecyl vinyl ether, acrylic acid, methyl acrylate, acrylic acid such as ethyl acrylate or esters thereof,
Methacrylic acid, methyl meteocrylate, meteocrylic acid 2-
Methacrylic acid or esters thereof such as ethylhexyl, maleic acid or esters thereof, acrylic derivatives such as maleic anhydride, acrylonitrile, and styrene; N-substituted maleimides such as Nt-butylmaleimide and N-cyclohexylmaleimide. These are used alone or in combination of two or more. Examples of the polymer which can be graft-polymerized with vinyl chloride include ethylene-vinyl acetate copolymer, ethylene-ethyl acrylate copolymer, chlorinated polyethylene, polyurethane, polybutadiene / styrene / methyl methacrylate copolymer, polybutadiene / acrylonitrile ( α-methyl) styrene copolymer, polybutyl acrylate, butyl rubber,
Examples include polystyrene, styrene / butadiene copolymer, and crosslinked acrylic rubber.

[0011] As the calcium compound, carbonate of calcium, silicates, glycerophosphate, acetate, propionate, heptanoate, 2-ethylhexyl phosphate, up to C ₈ -C ₂₂ acids such as stearic acid salt Higher fatty acid salt, 12
-Hydroxystearate, lactate, citrate, gluconate, sorbate, rosinate, ethyl acetoacetate, benzoate, isodecanoate, naphthenate,
Hydroxide and the like. An appropriate amount of the calcium compound is 0.01 to 1 part by weight based on 100 parts by weight of the vinyl chloride resin. More preferably, 0.05 to 0.5
It is used in a proportion of parts by weight, but when the amount is less than 0.01 part by weight, there is no effect of suppressing the zinc burning phenomenon. Conversely, when the amount exceeds 1 part by weight, it tends to be cloudy, and there is also a problem of initial coloring. come.

[0012] The compound of zinc, carbonates of zinc, orthophosphate, heptanoate, 2-ethylhexyl phosphate, higher fatty acid salt to C ₈ -C ₂₂ such as stearic acid salts, rosin acid salts, dibutyl dithiocarbamic Acid salt, isodecanoate, neodecanoate, naphthenate and the like. An appropriate amount of the zinc compound is 0.01 to 1 part by weight based on 100 parts by weight of the vinyl chloride resin. More preferably, it is used in a proportion of 0.05 to 0.5 part by weight, but if the amount added is less than 0.01 part by weight, the initial coloring is poor,
Conversely, when the amount exceeds 1 part by weight, a zinc burning phenomenon occurs, and the heat resistance durability deteriorates.

[0013] Epoxidized vegetable oils include epoxidized linseed oil, epoxidized soybean oil, epoxidized castor oil, epoxidized safflower oil, epoxidized linseed oil fatty acid butyl, octyl epoxy stearate, and 3- (2-xenoxy)-. Examples thereof include 1,2-epoxypropane, epoxidized polybutadiene, di-2-ethylhexyl epoxyhexahydrophthalate, and di-n-octyl epoxyhexahydrophthalate. An appropriate amount of the epoxidized vegetable oil is 0.1 to 5 parts by weight based on 100 parts by weight of the vinyl chloride resin. More preferably, it is used in a proportion of 0.5 to 4 parts by weight. However, if the addition amount is less than 0.1 part by weight, the flowability of the vinyl chloride resin is poor, and the calenderability is impaired. Conversely, if the amount exceeds 5 parts by weight, the resulting soft vinyl chloride sheet will have a lower softening temperature, and will have lower stiffness, resulting in problems in sheet formability and workability.

The β-diketone compound includes stearoylbenzoylmethane and palmitoylbenzoylmethane. The addition amount of the β-diketone compound is suitably from 0.01 to 1 part by weight based on 100 parts by weight of the vinyl chloride resin. More preferably, it is used in a proportion of 0.05 to 0.5 part by weight. When the amount is less than 0.01 part by weight, there is no effect of preventing initial coloring, and when the amount exceeds 1 part by weight, the amount increases. The improvement effect of the addition is lost.

[0015] Pentaerythritol and C11-C11
A mixed ester of a higher fatty acid of 20 and a saturated dibasic acid having 4 to 6 carbon atoms is used as a so-called lubricant, and the amount of the mixed ester is 0.05 to 0.1 with respect to 100 parts by weight of the vinyl chloride resin. 5 parts by weight are suitable. More preferably, it is used in a proportion of 0.1 to 0.4 part by weight. When the amount is less than 0.05 part by weight, the effect as a lubricant is not sufficient, and when it exceeds 0.5 part by weight, cloudiness is caused. Occurs, bleeds,
Easy to bloom. The component ratio between the higher fatty acid and the saturated dibasic acid in the mixed ester is 6 to 12 mol of the higher fatty acid and 1 to 4 mol of the saturated dibasic acid, particularly 6 to 12 mol of the higher fatty acid.
One to two moles of a saturated dibasic acid is preferred to 8 moles because the lubricity is stable. When the number of carbon atoms of the higher fatty acid and the saturated dibasic acid is less than 11 and less than 4, respectively, there is no lubricating effect. On the contrary, if the number of carbon atoms of the higher fatty acid is more than 20, or 6 carbon atoms
If it exceeds, cloudiness occurs, and bleeding and bloom are easily caused. Therefore, the number of carbon atoms of the higher fatty acid and the saturated dibasic acid is desirably 11 to 20 and 4 to 6, respectively. As higher fatty acids having 11 to 20 carbon atoms, lauric acid, myristic acid, undecanoic acid, tridecanoic acid,
Pentadecanoic acid, palmitic acid, stearic acid, margaric acid, isostearic acid, 12-hydroxystearic acid, oleic acid, linoleic acid, ricinoleic acid, linoleic acid, n-heneicosanoic acid, behenic acid, n-trichosanoic acid, arachidonic acid, etc. And these are used in one kind or in combination of two or more kinds. 4 carbon atoms
As the saturated dibasic acids of to 6, adipic acid, succinic acid,
Glutanic acid and the like are used, and these are used alone or in combination of two or more. Among the mixed esters composed of the above components, mixed esters composed of pentaerythritol, stearic acid and adipic acid and mixed esters composed of pentaerythritol, oleic acid and adipic acid are particularly preferable from the viewpoint of lubricating effect. In addition, when a higher fatty acid is used alone as a lubricant, the initial coloring is deteriorated, for example, by reacting with an organic phosphite added as a stabilizing aid, and the sheet becomes cloudy or the amount of volatilization during processing increases. Various problems occur.

The rigid vinyl chloride sheet of the present invention may contain an organic phosphite compound usually used as an additive for vinyl chloride resin. Examples of the organic phosphite compound include tris (nonylphenyl) phosphite, 2-tert-butyl-α (3-tert-butyl-4-hydroxyphenyl) p-cumenylbis (p
- nonylphenyl) phosphite, 4'4- isopropylidene - diphenol alkyl (C ₁₂ -C ₁₅₎ phosphite. Furthermore, we improve light stability,
An ultraviolet absorber can be added for the purpose of preventing light deterioration of the package contents. These include benzophenones, benzotriazoles, salicylates, substituted acrylonitriles, various metal salts or metal chelates, especially nickel or chromium salts or chelates, triazines, piperidines.

[0017] Also, it sneaks between the PVC molecules, weakens the force between the PVC molecules, lowers the heating temperature to increase the fluidity, and at the same time, lowers the second order transition temperature to enable micro Brownian motion of the PVC molecule segments, thereby providing soft elasticity. To get a gel,
Usually, additives for vinyl chloride resin include phthalic acid ester compounds, aliphatic dibasic acid ester compounds, phosphate ester compounds, hydroxy polycarboxylic acid ester compounds, fatty acid ester compounds, polyhydric alcohol ester compounds, polyester compounds, and the like. But with a softening temperature of 50
Since the temperature is 80 ° C., the amount added is naturally limited.

The rigid PVC sheet of the present invention is JIS K6
Flexible temperature is 50 to 8 as measured by flexible temperature test of 734
0 ° C. Further, the temperature is preferably 55 to 70 ° C. The higher the softening temperature, the lower the heat resistance, that is, the less change in appearance when heat is applied. Conversely, if the temperature is lower than 50 ° C., the heat resistance is poor, and the change in appearance when heat is applied is large, and there is a problem of moldability in a subsequent process. These softening temperatures can be adjusted relatively easily by appropriately selecting the types and amounts of the above-mentioned additives.

The thickness of the rigid vinyl chloride sheet of the present invention is 0.05 to 1.0 mm. 0.15
0.5 mm is preferred. If the thickness of the sheet is less than 0.05 mm, it cannot be used because of insufficient moisture-proof properties against the contents of the package, gas barrier properties and other strengths as a package. Conversely, if it exceeds 1.0 mm, the sheet strength is so high that handling in post-processing becomes difficult, and it cannot be used. The thus obtained rigid vinyl chloride sheet of the present invention may further contain, if necessary, for example, a lubricant, a crosslinking agent, a pigment, a filler, a foaming agent, an antistatic agent, an anti-fogging agent, and a plate-out preventing agent. , Surface treatment agents, processing aids, release agents,
A reinforcing agent or the like can be appropriately used. Further, the rigid vinyl chloride sheet of the present invention can be subjected to a sheeting process by a calendering method, but the working method is not particularly limited here, and for example, a known method such as a T-die method or an inflation method can be adopted.

[0020]

The present invention will be described below with reference to examples and comparative examples, but the present invention is not limited only to the description of the examples. The components shown in Tables 1 to 3 were blended, mixed and dried up with a Henschel mixer, and the cooled composition was pre-kneaded with a conventionally known two-roll, and then, with a four-roll reverse L-type calender roll. Hard vinyl chloride sheets were prepared at various predetermined thicknesses. Each measurement item of the obtained sheet was measured by the following method. The mixed ester and pentaerythritol, adipic acid and oleic acid, respectively (1: 1:
6) Mixed esters, (1: 1: 6) mixed esters of sorbitan, adipic acid and oleic acid and (1: 1: 6) mixed esters of diethylene glycol, adipic acid and oleic acid.

The evaluation method is as follows. (1) Initial coloring property The obtained sheets were stacked, preheated at 180 ° C for 3 minutes, and hot-pressed at a surface pressure of 20 kg / cm ² for 2 minutes.
An initial colored plate having a thickness of mm was prepared. The yellowness (b value) of the initial colored plate was measured with a color difference meter. The larger the value of yellowness (b value), the worse the initial coloring property. (2) Heat resistance (blackening time) Place the obtained sheet in a gear type aging tester set at 180 ° C, take out a sample every 10 minutes, and measure the time (min) until browning or blackening. did. The longer the time (minutes), the better the heat resistance (blackening time). (3) Calendering workability The calendering workability was evaluated by visually observing the roll releasability of the sheet during calendering, and contamination of the roll. ○
Indicates no problem, △ indicates a problem depending on conditions,
× indicates that there is a problem and processing cannot be performed. (5) Flexible temperature Measured according to JIS K6734. (6) Secondary workability The shape when PTP was formed by a hot plate press forming machine with a plug and the feeding of the formed sheet were visually observed. ○ means no problem, △ means trouble depending on conditions, × means problem and cannot be processed.

The evaluation results are shown in Tables 1 to 3.

[Table 1]

[0023]

[Table 2]

[0024]

[Table 3]

[0025]

According to the rigid vinyl chloride sheet of the present invention, it is excellent in thermal stability and calendering workability, can cope with an increase in the size and speed of a processing machine, and has transparency, workability and hygiene. It is possible to provide a packaging material for foods, medicines and the like having excellent properties.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁶ Identification code Agency reference number FI Technical display location C08K 5/11 KGY C08K 5/11 KGY 5/15 KHC 5/15 KHC // B29K 27:06 B29L 7:00

Claims (5)

[Claims] 1. A calcium compound of 0.01 to 1 part by weight, a zinc compound of 0.01 to 1 part by weight, an epoxidized vegetable oil of 0.1 to 5 parts by weight, a β-diketone based on 100 parts by weight of a vinyl chloride resin. A hard vinyl chloride sheet comprising a composition to which 0.01 to 1 part by weight of a compound and 0.05 to 0.5 part by weight of an ester compound are added. 2. The vinyl chloride resin has an average degree of polymerization of 600.
The rigid vinyl chloride sheet according to claim 1, wherein 3. The ester compound according to claim 1, wherein the ester compound is a mixed ester of pentaerythritol, a higher fatty acid having 11 to 20 carbon atoms, and a saturated dibasic acid having 4 to 6 carbon atoms. The rigid vinyl chloride sheet as described in the above. 4. The hard vinyl chloride sheet according to claim 1, wherein a soft temperature is 50 to 80 ° C. as measured by a soft temperature test according to JIS K6734. 5. The rigid vinyl chloride sheet according to claim 1, wherein the thickness of the sheet is 0.05 to 1.0 mm.