JPS61137711A - Porous plastic molding and manufacture thereof - Google Patents

Abstract

PURPOSE:To provide a good quality porous plastic molding by a method wherein photo-setting resin composition is turned into the state of slurry, expansion- molded and photo-set by being irradiated with active light. CONSTITUTION:Various compositions are employed as photo-setting resin composition. Especially, as for photopolymerizable composition, photo-ionic polymerization such as photo-radical polymerization of unsaturated group or ring opening polymerization of oxirane ring is utilized. The expanded photo-setting resin composition is formed into the desired shape and photo-set by being irradiated with active light in order to obtain a foamed molding. As for the generating source of the active light, the source, which generates enough ultraviolet rays, such as mercury vapor lamp, xenon lamp, metal halide lamp, chemical lamp or the like, is preferable, accordingly, the molding has excellent heat insulating property and cushioning property and consequently is useful for heat insulating material, cushioning material and packaging material.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a novel porous plastic molded article and a method for producing the same, and more specifically, it is useful as a heat insulating material, a cushioning material, a packaging material, etc.

A porous plastic molded article made of a photocurable resin composition, and a method for easily manufacturing a porous plastic molded article by irradiating active light after or simultaneously with full foam molding of the photocurable resin composition. It is something.

Prior Art Conventionally, porous plastic molded products include polystyrene foam, rigid and flexible polyurethane foam, polystyrene foam, polyvinyl chloride 7 ohm, m
Foam molded products such as A7 ohm, polyglopyrene foam, and phenolic resin foam are known, and these foam molded products have characteristics such as heat insulation, cushioning properties, porosity, and apparent low specific gravity. 1. For example, it can be used as cushioning material for automobile and railway vehicle seats, furniture and bedding, insulation material for ships, buildings, plants, etc., as well as various packaging materials, transportation shoes/con materials, sound absorbing materials, etc. It is widely used in many fields.

Until now, such porous plastic molded products (1
) A method of using a blowing agent that causes a decomposition reaction with heat or subcomponents to generate gas, (2) A method of generating gas and foaming in the process of polycondensation of 5111 compounding agent KJ, ( 3) A method of absorbing inert gas under high pressure and foaming when the pressure returns to normal.

(4) Manufactured by a method such as fusion molding of expandable beads containing an easily volatile liquid.

However, in all of these methods,
Although the first step and the molding step are combined to obtain a foam molded product, there are drawbacks such as difficulty in obtaining uniform and fine cells and a desired expansion ratio. In addition, in methods 1) and (2) above, the pot life after preparing the molding material is short, and in method (3), in order to obtain various foam molded products, the @ sense and pressure must be strictly controlled. There are some problems, such as the need for a controllable and costly device. Furthermore, the method using expandable beads (K(4)) has problems such as the easily volatile liquid used tends to be flammable and the generated gas is harmful, so it must be handled with care.

Problems to be Solved by the Invention The purpose of the present invention is to solve the above-mentioned problems in the conventional method of manufacturing porous glass snack molded products, and to easily produce a molded article of good quality using completely different means than the conventional methods. Our goal is to provide a complete range of porous plastic molded products.

Means for Solving the Problems As a result of extensive research, the inventors of the present invention found that a photocurable resin composition was used as a material, and after foam molding this in a slurry form, or at the same time, irradiation with active light was performed. It was discovered that the above object can be achieved by photocuring, and based on this knowledge, the present invention was completed.That is, the present invention provides a photocurable resin composition in a foamed state. A porous plastic molded article made of a photocured product of a material and a photocurable resin composition made into a slurry, which is foam-molded or simultaneously irradiated with actinic light to photocure. The present invention provides a method for manufacturing high-quality plastic molded products.

In the present invention, as a photocurable resin composition, 80°C
A material that exhibits fluidity and can be foamed at the following temperatures, preferably 60° C. or lower, is used. If the degree of fluidity exceeds 80°C, it is undesirable because the mold needs to be heated during molding, resulting in constraints from the mold material and the composition gelling due to heat.

Various types of compositions can be used as such photocurable resin compositions, and photopolymerizable compositions are particularly applicable.

This is preferable because it is possible to obtain products having various physical properties by selecting the composition. Examples of such compositions include those that utilize radical ionic polymerization such as radical polymerization of unsaturated groups and ring-opening polymerization of oxirane rings. Typical examples include compositions whose main components are a prepolymer having an ethylenically unsaturated group and a photopolymerization initiator, with optionally added an ethylenically unsaturated monomer or a thermal polymerization inhibitor; Examples include those in which various polymers such as acrylic resin, polyamide, polyurethane, polyvinyl, alcohol, polystyrene, etc. are dissolved and mixed with a saturated monomer, and a photopolymerization initiator is added.

Examples of the prepolymers having ethylenically unsaturated groups include unsaturated polyesters, unsaturated polyurethanes,
Oligoester acrylate, oligoester methacrylate, unsaturated polyamide.

Examples include unsaturated polyimide, unsaturated polyether, unsaturated polyacrylate, unsaturated polymethacrylate, various modified products thereof, and various rubber compounds having a carbon-carbon double bond.

These prepolymers usually have an average molecular weight of substantially 500 or more.

Specific examples of such prepolymers include unsaturated polyesters and alkyds such as maleic acid,
Unsaturated dibasic acids such as fumaric acid and itaconic acid or their acid anhydrides and ethylene glycol, fluoropylene gellicol, diethylene glycol, triethylene glycol, glycerin, trimethylolpropane, pentaerythritol, 1, 4 having a terminal hydroxyl group - Polyesters with polyhydric alcohols such as polybutadiene, hydrogenated or non-aqueous 1,2-polybutadiene-acrylonitrile copolymers, co/part of the acid components, phosphoric acid, adipic acid.

Examples of unsaturated polyurethanes include polyesters substituted with saturated polybasic acids such as phthalic acid, isophthalic acid, phthalic anhydride, and trimellitic acid, and polyesters modified with drying oil fatty acids or semi-drying oil fatty acids.
Addition-polymerizable unsaturated groups are introduced using the terminal ino-7anate group or hydroxyl group of a compound linked via a urethane group derived from a polyol and polyisocyanate having more than 10 terminal hydroxyl groups, such as the above-mentioned polyhydric J, 4- having a polyol terminal hydroxyl group such as alcohol, polyester polyol, polyether polyol, etc.
Polybutadiene, hydrogenated or non-hydrogenated 1,2-polybutadiene, butadiene-styrene copolymer, butadiene-acrylonitrile copolymer, etc. with toluylene diynianate, diphenylmethane-4,47-ditucyanate, hexamethylene diisonanate An unsaturated group is introduced by utilizing the reactivity of the terminal incyanate or hydroxyl group of polyurethane with a polyincyanate such as.

Alternatively, an unsaturated group may be introduced by reacting an incyanate with a compound having an active hydrogen such as a hydroxyl group, a carboxyl group, or an amine group among the unsaturated carboxylic acids or esters thereof, or a reaction between an unsaturated carboxylic acid having a carboxyl group and a hydroxyl group. Examples include a compound into which an unsaturated group is introduced by reaction, or a compound in which the above-mentioned unsaturated polyester is linked with a polyisocyanate. In addition, oligoester acrylates can be produced by co-condensing acrylic acid or methacrylic acid in an ester reaction system of polybasic acid and polyhydric alcohol and adjusting the molar ratio of each to obtain a molecular weight of 200 to 500.
About 0: 1 For example, adipic acid, phthalic acid, diisophthalic acid, acid anhydride, etc., and ethylene glycol, propylene glycol, diethylene glycol, triethylene glycol.

Evoquin acrylates 1, which are condensed with polyhydric alcohols such as chrycerin, trimethylolpropane, and pentaerythritol in the coexistence of acrylic acid or methacrylic acid. Ester of acrylic acid or methacrylic acid with a compound having an epoxy group obtained by polycondensation reaction with epichlorohydrin or alkylene oxide, polymeric compound having an addition-polymerizable carbon-carbon double bond in the side chain, such as polyvinyl alcohol, cellulose A compound obtained by reacting a polymer compound with a hydroxyl group with an unsaturated carboxylic acid or its acid anhydride, or a polymer with a carboxyl group such as a polymer or copolymer of acrylic acid or methacrylic acid. Copolymers of glycidyl acrylate or methacrylate, such as compounds in which unsaturated alcohol, glycidyl acrylate or methacrylate, etc. are ester bonded, reaction products of maleic anhydride-containing copolymers and allyl alcohol, hydroxyalkyl acrylate, or methacrylate, etc. Examples include a reaction product of a copolymer contained as a component and acrylic acid or methacrylic acid. In addition, various rubber compounds include (1) 1,4-polybutadiene, 1,2-polybutadiene, butadiene-styrene copolymer, phtadiene-acrylonitrile copolymer + EP
DM, (II) hydrogenated product of the above (1), inbutysea isobrene copolymer. Examples include ethylene propylene copolymers and unsaturated modified rubbers in which ethylenically unsaturated groups are introduced into various rubber compounds shown in (1) using known techniques. The compound (1) above can be used as is, but in order to introduce the unsaturated group, it is convenient to use various rubber compounds having one terminal functional group. Also, 1,
In the case of a rubber compound having a 2-polybutadiene segment, the unsaturated group can be easily introduced by adding maleic anhydride to the compound.

Various known compounds can be used as the ethylenically unsaturated monomer, and examples of such compounds include unsaturated carboxylic acids such as acrylic acid and methacrylic acid, or esters thereof, such as alkyl-, cycloalkyl-, , alkyl halide.

Alkoxyalkyl-, hydroxyalkyl-.

Aminoalkyl-, tetrahydrofurfuryl-.

Allyl-, greenylene-, benzyl-, phenoxy-acrylates and methacrylates, mono- or diacrylates and methacrylates of alkylene glycols, polyoxyalkylene glycols, trimethylolpropane triacrylates and methacrylates, pentaerythritol tetraacrylates and methacrylates, acrylamide, Methacrylamide or derivatives thereof, such as N-ff1Hl-N,N'-substituted acrylamide and methacrylamide with an alkyl group or hydroxyalkyl group, diacetone acrylamide and methacrylamide, N,N'-alkylenebisacrylamide and methacrylamide, etc. , allyl compounds such as allyl alcohol, allyl incyanate, diallyl phthalate,
Maleic acid-maleic anhydride, fumaric acid or esters thereof, such as triallyl cyanurate.

Other unsaturated compounds such as styrene, vinyltoluene, divinylbenzene-N-vinylcarbazole, N-vinylpyrrolidone, etc. may be mentioned. can. In addition, a part of these monomers may be added to an azide compound 1 such as 4.4'-diazidostilbene, P-phinidine-bisazide, 4.4'
->azidobenzophenone+4.4'-diazidophenylmethane.

4.4'-Diazidochalcone, 2,6-di(4'-diazidobenzal)-cyclohexanone, 4.4'-diazidostilbene-α-carboxylic acid-4,4'-diazidodiphenyl, 4,4' -Diazidostilbene-2,2
'-Sodium disulfonate may also be used instead.

These monomers are used in an amount of 0 per 100 parts by weight of the prepolymer.
It may be added in a range of 200 parts by weight.

On the other hand, as the one-component polymerization initiator, various known photosensitizers such as benzoyl, benzoin methyl ether, benzoin ethyl ether, benzoin propyl ether, pentuin inoclovir ether, penguin butyl ether, penzoin butyl ether, 2, 2-dihydroxy-2-phenylacetophenone, 2.2-diftquine-2-phenylacetophenone, 2.2-jethoxy-2-phenylacetophenone, 2,2-shedquinacetophenone, benzophenone + 4.4'-bisdialkylaminobenzophenone -4-dimethylaminobenzoic acid, 4-dimethylaminobenzoic acid alkyl ester + 2-ethylanthraquinone, xanthone, 7 tons of thioxa, 7 tons of 2-chlorothioxa, etc. can be used. These photosensitizers.

Usually, weights ranging from o, ooi to 10 parts by weight are used for the composition.

In addition, examples of thermal polymerization inhibitors include hydroquinone,
Mono-tert-butylhydroquinone, benzoquinone-2,s
-diphenyl-p-benzoquinone.

Picric acid, di-p-fluorophenylamine.

p-methoxyphenol, 2,6-di-tert-butyl-p-
Examples include cresol. These thermal polymerization inhibitors are for preventing thermal polymerization reactions (dark reactions), and therefore, the amount of the thermal polymerization inhibitors added is 0.00000% relative to the total amount of prepolymer and monomer. It is preferable to select it within the range of 0.005 to 5 weight ratio.

Other photopolymerizable compositions include 1, for example, a composition comprising a compound that releases a Lewis acid and a compound that undergoes ionic ring-opening polymerization with a Lewis acid, such as an oquinrane-containing compound (Japanese Patent Publication No. 14277/1983, Special Public Service 1977-
14278), and a composition utilizing a photoaddition reaction of polyethylene/polythiol (Japanese Patent Publication No. 46-29525).

In the present invention, it is necessary to first form such a photocurable resin composition into a slurry form and foam it while maintaining that state. If it has fluidity, it can be used as it is as a slurry, or if it is solid, it can be made into a slurry by adding a solution.

Next, this slurry may be foamed by either physical foaming by blowing inert gas or the like, or chemical foaming by mixing a foaming agent that decomposes to generate gas and foaming by heating, etc. Physical foaming is desirable because it does not require any processing conditions. As the physical foaming method, for example, a method is used in which air is drawn in using a mixer or an agitator to create foam, and a method is created in which air, nitrogen gas, carbon dioxide gas, etc. is stirred and foamed while being blown into the material.

At this time, it is effective to add a surfactant to increase foaming properties and foam stability.

In addition, the shape of the mixer or agitator, the stirring speed, the amount of gas blown, the amount of surfactant added, etc. will depend on the desired expansion ratio, pore size, apparent density, etc. of the resulting foam molded product. They are selected accordingly.

The photocurable resin composition that has been foamed in this way is molded into a desired shape by injecting it into various molds or spreading it as it is on a belt, and then irradiated with active light. The foam is cured with light to obtain a foam molded product. When casting and irradiating actinic rays, after one casting, cover with a transparent body such as glass or transparent plastic sheet 6 film, or leave it open and irradiate active rays from the transparent body or the open side. . In this case, the composition may be injected after setting the mold and the transparent body, or glass or glass can be used as the mold material.
A transparent mold made of transparent plastic or the like may be used and active light may be irradiated from both sides or from all sides for efficient photocuring.

In the present invention, photocuring may be carried out after foam molding as described above, but it is also possible to perform foam molding in a transparent mold and photocuring by irradiating actinic light at the same time. Alternatively, it is also possible to photocure a foamed material by irradiating it with active light while molding it.

In the present invention, since active light is irradiated to photocure, there is no need to apply heat or pressure at all, unlike conventional methods. Therefore, the material for the mold can be selected from a wide range of materials, and the method for manufacturing the mold is It also becomes easier. For example, in addition to conventionally used molding molds, various plastics, brazing materials 1
Materials such as plaster and clay that can be easily molded can be used.

On the other hand, a method of irradiating active light while spreading a foamed photocurable composition in the form of a belt is effective as a continuous method for producing foam sheets.

As the active light used for photocuring, those that generate a large amount of ultraviolet light, such as a mercury lamp, a xenon lamp, a metal halide lamp, and a chemical lamp, are suitable, and solar sources can also be used.

The porous plastic molded product thus obtained is 1
Usually the foaming ratio is in the range of 2 to 100 times, the apparent density is 0.0
It is molded to a range of 1 to 0.7 P/CC and used as heat insulating materials, packing materials, etc. Those with a foaming ratio of less than 2 times do not have the characteristics of a foam;
If it is more than twice that, the mechanical strength will be low and it is not practical. Also, the apparent density is usually 0.01 to 0.7? /CC
is within the range of Furthermore, the pores are fine and uniformly distributed, and the size of the pores is usually in the range of 0.1 μm to 500 μm in diameter.

Effects of the Invention The method of the present invention uses a photocurable resin composition as the material for the molded product, and unlike conventional methods, it does not use a blowing agent or easily volatile liquid, nor does it require pressure. A porous plastic molded product can be obtained by performing a foaming process such as mechanical foaming and photo-curing.Therefore, no expensive equipment is required, and the workability is good, and the mold material can be selected from a wide range of materials. It is a method of extremely high industrial value, as it allows for on-site foaming, the foaming ratio can be easily controlled, and the resulting foam has uniform and fine pores.

Furthermore, the porous plastic molded article of the present invention has good heat insulating properties and cushioning properties, and is useful as, for example, a heat insulating material, a cushioning material, and a packaging material.

Example Next, the present invention will be explained in more detail with reference to Examples.

Example 1 35 parts by weight of styrene was added to 100 parts by weight of an unsaturated polyester resin (acid value 28) obtained by condensing diethylene glycol, fumaric acid and phthalic anhydride in a molar ratio of 1:0.5:0.5. part, methyl methacrylate 1
5 parts by weight, 1.5 parts by weight of benzoin butyl ether, 0.5 parts by weight of 2,6-tert-butyl-p-cresol.
05 parts by weight and 2 parts by weight of lauryl alcohol sulfate salt were added to prepare a photocurable resin composition.

This composition was vigorously stirred with a homomixer while blowing nitrogen gas into it to form a soft cream. This foamed composition was injected into a mold for a 511 wing set on a glass plate treated with a silicone mold release agent, and covered with a polyester film of -50μ thickness. 5 with a 2Th high pressure mercury lamp.
Irradiate ultraviolet rays for 1 minute from a distance of 01 and photocure 1.
Next, the glass plate and polyester film were removed to obtain a foamed sheet approximately 5 mm thick.

The foaming ratio of this product is about 4 times, and the apparent density is 0.3? /
cc - and the pores were uniformly distributed and had an average diameter of about 30 microns, making it useful as a heat insulator.

Example 2 Polyethylene adipate diol (molecular weight z, ooo)
400 parts by weight, 600 parts by weight of ethylene oxide-propylene oxide copolymer (block copolymer diol containing 35% by weight of ethylene oxide units, molecular weight 2,000), 105 parts by weight of trilene ynon anate, 1 weight by weight of dibutyltin laurate. 2-hydroxyethyl methacrylate and 0.1 part by weight of hydroquinone were added, and the mixture was reacted at 70°C for 3 hours to produce a polymer having in-a-atom groups at both ends.
The mixture was reacted for 2 hours to produce a polyurethane prepolymer having all unsaturated bonds at the ends.

To 300 parts by weight of this polyurethane prepolymer (containing residual 2-hydroxyethyl methacrylate), 20 parts by weight of polyethylene glycol dimethacrylate, 30 parts by weight of lauryl methacrylate, parts by weight of trimethacrylate rO-dimethogyne phenyl Acetophenone Si band was added and mixed to prepare a photocurable resin composition.

This composition was vigorously stirred with a homomixer to form a cream, and this was used to create a packaging cushion material for transporting pottery using the following procedure.

The above creamy composition was poured into a glass tank coated with a silicone mold release agent, and then a 2KW high pressure was applied from the bottom and side of the glass tank while pressing the pottery so that half of it was immersed in the composition. After exposing it to a mercury lamp for 1 minute each, it was removed from the water tank and taken out to prepare half of the packaging cushion material. Next, do the same operation on the remaining half of the pottery.

I created the other half.

The foam obtained in this way has an expansion ratio of about 5 times, an apparent density of 0.25 f/cc, and pores are uniformly dispersed with an average diameter of about 30 μm. It was excellent as a cushioning material for transportation.

Claims (1)

[Claims] 1. A porous plastic molded article comprising a photocured product of a photocurable resin composition in a foamed state. 2. A method for producing a porous plastic molded article, which comprises forming a photocurable resin composition into a slurry, foam-molding the composition, and then photocuring it by irradiating active light or at the same time.