JPH05209128A - Molded article of crosslinked polymer, its production and composition thereof - Google Patents

Abstract

PURPOSE:To obtain a molded article of crosslinked polymer having improved heat distortion temperature and flexural modulus by thermally molding a radically curable active hydrogen-containing thermoset resin powder under pressure in the presence of a radical initiator. CONSTITUTION:A thermoset resin such as polydicyclopentadiene containing radically crosslinkable active hydrogen is ground by using a grinder and the prepared powder is thermally molded under pressure in the presence of a radical initiator such as t-butyl hydroperoxide to give the objective molded article.

Description

Detailed Description of the Invention

[0001]

[Industrial field of application] In recent years, the disposal of plastics has become a social problem, and the need for recycling plastics has been emphasized from the viewpoint of environmental protection and resource conservation. The present invention relates to the recycling of plastics, and to a useful remolded product from a thermosetting resin, which has been conventionally difficult to recycle.

[0002]

2. Description of the Related Art Up to now, regarding the recycling of plastics, thermoplastic resins which can be recovered and remelted have been advantageous. However, in reality, the recycled moldings are used at best as miscellaneous items such as piles, display boards, and simple containers, and even it is difficult to recover such waste products in a remeltable form.

On the other hand, in the case of a thermosetting resin, it cannot be recovered and remelted, and it is difficult to recover it as a monomer in most cases, which is a problem from the viewpoint of environmental protection such as incineration and landfill and resource conservation. Only many methods could be taken.

[0004]

Therefore, the inventor of the present invention
It was considered that the method of crushing the recovered thermosetting resin having radically crosslinkable active hydrogen and then thermocompression molding is effective.
However, even in that case, as a result of intensive studies to obtain a molded product having a new function, based on the finding that only a product having inferior performance can be obtained by thermocompression molding by a usual method, the present invention It was thought of. Furthermore, the present invention has been made as a result of intensive studies from the viewpoints of physical properties, fluidity, and moldability so that molding can be performed under the molding conditions of SMC which is already widely used.

[0005]

DISCLOSURE OF THE INVENTION The present invention provides a method for producing a crosslinked polymer molding by thermocompressing a thermosetting resin powder having radically crosslinkable active hydrogen, and a crosslink obtained by the method. The present invention relates to a polymer molded product and a composition used in such a method.

[0006] That is, the present invention is a cross-linking method comprising thermo-compressing a composition comprising a powder of thermosetting resin having active hydrogen capable of radical cross-linking, a polymer component for imparting fluidity and a radical initiator. It is a method for producing a polymer molded article.

It is preferable that the composition further contains a reinforcing agent and / or a thickening agent and is thermocompression molded.

The present invention includes a crosslinked polymer molded product obtained by the above-mentioned production method.

Further, the present invention includes a composition comprising a powder of thermosetting resin having active hydrogen capable of radical crosslinking, a polymer component imparting fluidity and a radical initiator. In such a composition, a composition further containing a reinforcing agent and / or a thickening agent is suitable.

In the present invention, the powder of the crosslinked polymer molding obtained by the above-mentioned method of the present invention is used again as the powder of the thermosetting resin having active hydrogen capable of radical crosslinking,
It includes a method for producing a crosslinked polymer molded product, which comprises thermocompression molding with a polymer component that imparts fluidity and a radical initiator. That is, the method includes thermocompression molding of the crosslinked polymer molding obtained by the present invention by the method of the present invention and recycling. Such recycling can be performed multiple times.

According to the present invention, the thermosetting resin powder having the above-mentioned radical crosslinkable active hydrogen is thermocompression-molded together with the polymer component for imparting fluidity and the radical initiator to obtain a conventional thermosetting resin. Although it is completely different from the properties of the cured resin, it is possible to obtain an attractive molded product in terms of performance.
That is, a molded product having a greatly improved heat distortion temperature can be obtained. The reason for this is not clear, but it is presumed that the crosslinking has advanced to a higher order.

Further, in the present invention, by adding a polymer component and a radical initiator which further impart fluidity, powder fusion easily occurs and molding becomes easy.

By adding a polymer component which imparts fluidity, the fluidity at the time of molding is improved, and a molded article having a smooth surface and gloss can be obtained.

The radically crosslinkable active hydrogen used in the present invention means hydrogen at the allyl position, benzyl position, and α-position of a hetero atom.

Specific examples of the thermosetting resin having active hydrogen capable of radically crosslinking are polydicyclopentadiene, unsaturated polyester, polyurethane, epoxy,
Examples thereof include polyimide, diallyl phthalate and phenol resin. Here, the polydicyclopentadiene has hydrogen at the allylic position. Unsaturated polyesters, polyurethanes, epoxies, polyimides and diallyl phthalates have hydrogens in the α-position of the heteroatoms. Unsaturated polyesters and phenol resins have benzylic hydrogen. Particularly, a thermosetting resin made of polydicyclopentadiene is preferable.

In the present invention, the powder of thermosetting resin having active hydrogen capable of radical crosslinking is 50% of the total composition.
It is used in the range of ~ 95 wt%, preferably 55-90 wt%.

There is no particular problem even if these resins contain a rubber component for physically or chemically improving properties, glass for reinforcement, fillers, pigments, light stabilizers, etc. Glass fiber, carbon fiber, aramid fiber, alumina fiber and other organic and inorganic fibers, metal wires, and a rubber component are added separately to improve impact resistance as a reinforcing agent for modifying the finished molded product. It may be hot pressed.

In general, in order to enable the molding material to be molded under the molding conditions of SMC, in order to improve the resin impregnation of the reinforcing fibers during the material production, the polymer component which imparts fluidity is low. It must be viscosity. On the other hand, if the polymer component that imparts fluidity remains low in viscosity, it is often inconvenient to handle because it is too soft and sticky or the material is brittle. Further, the material may easily flow in the mold and a good molded product may not be obtained. Therefore, in order to improve the impregnation of resin into the reinforcing fibers during material production, the polymer component that imparts fluidity must have a low viscosity, but the viscosity increases before molding, making it easy to handle. Is required to become. In particular, by forming the material at the time of molding into a sheet shape, it is possible to achieve good moldability and molding with a high degree of freedom.

The polymer component which imparts fluidity includes low melting point rubber and liquid rubber. The molecular weight is preferably about 700 to tens of thousands. Examples of the low melting point rubber include styrene isoprene rubber used in hot melt adhesives. The melting point is preferably 10 to 150 ° C. Examples of the liquid rubber include liquid polyisoprene, liquid polybutadiene, liquid 1,2-polybutadiene, liquid styrene-butadiene rubber, liquid polychloroprene, liquid acrylonitrile-butadiene rubber, liquid polyolefin glycol and the like. Generally, the polymer component agent that imparts such fluidity is 5 to 50% of the total weight,
More preferably, it is used in the range of 5 to 30%.

In the present invention, when the molding material is poor in handleability only with the component imparting fluidity, a thickener can be added to facilitate handling of the material. As the thickening method, a method using radical polymerization or a method of increasing the molecular weight by mixing a carboxyl group and an oxide and / or hydroxide of an alkaline earth metal can be adopted. That is, when a low melting point rubber having a radically polymerizable functional group such as styrene isoprene rubber or a liquid rubber such as 1,2-polybutadiene is used as a polymer component that imparts fluidity, a radical polymerization initiator is used. It can be used as a thickener.

Further, 1,2-having a carboxylic acid at the terminal
When polybutadiene liquid rubber or the like is used as a polymer component that imparts fluidity, an alkaline earth metal oxide and / or hydroxide can be used as a thickener.

When an unsaturated polyester resin is used, it is preferable to use an oxide of an alkaline earth metal and / or a hydroxide as a thickener.

Particularly, 1,2-having a carboxylic acid at the terminal
A combination of a polybutadiene liquid rubber and an oxide and / or hydroxide of an alkaline earth metal, or a combination of an unsaturated polyester resin and an oxide and / or hydroxide of an alkaline earth metal is preferable. A part of the polymer obtained by the metathesis polymerization of cyclic olefins such as dicyclopentadiene has a structure in which a carboxylic acid is introduced by oxidation, so that it reacts with an oxide or hydroxide of an alkaline earth metal and increases. Since it contributes to viscosity, a particularly preferable effect is given.

Here, the alkaline earth metal oxide and hydroxide are preferably a combination of magnesium oxide, magnesium hydroxide, calcium oxide, calcium hydroxide and a mixture thereof.

Under the molding conditions of SMC, which is technically established and widely used to use the recovered material, it is possible to recycle a molded article having new performance without any problem in productivity. It can be said that the invention is useful not only from the above but also from the standpoint of environmental protection and resource protection.

The radical initiator used in the present invention may be any type of peroxide such as hydroperoxides, dialkyl peroxides, diacyl peroxides, peroxyesters and ketone peroxides, depending on the conditions such as reaction temperature and molding time. Selected together. Specifically, t-butyl hydroperoxide, cumene hydroperoxide, diisopropylbenzene hydroperoxide, p-methane hydroperoxide, 2,5-dimethyl-2,5-dihydroperoxyhexane, 2,5-dimethyl-2,5- Dihydroperoxyhexene, pinene hydroperoxide, di-t-butyl peroxide, di-
t-amyl peroxide, di-t-butylcumyl peroxide, dicumyl peroxide, 2,5-dimethyl-
2,5-di-t-butylhydroperoxyhexane,
2,5-Dimethyl-2,5-di-t-butylhydroperoxyhexene, α, α'-bis-t-butylperoxydiisopropylbenzene, 1,1-bis-t-butylperoxy-3,3,5- Trimethylcyclohexane,
n-Butyl-4,4-bis-t-butylperoxyvalerate, 2,2-bis-4,4-t-butylperoxycyclohexylpropane, 2,2-bis-t-butylperoxybutane, 1,1- Di-t-butylperoxycyclohexane, caprylide peroxide, lauryl peroxide, styryl peroxide, succinic acid peroxide, benzoyl peroxide, p-chlorobenzoyl peroxide, 2,4-dichlorobenzoyl peroxide, t-butylperoxyacetate, t
-Butylperoxy-2-ethylhexanoate, t-
Butyl peroxylaurate, t-butyl peroxybenzoate, di-t-butyl peroxyphthalate,
2,5-di-t-butyl-2,5-dibenzoylperoxyhexane, 2,5-di-t-butyl-2,5-dibenzoylperoxyhexene, t-butylperoxymaleic acid, t-butylperoxy Examples thereof include isopropyl carbonate, methyl ethyl ketone peroxide, methyl isobutyl ketone peroxide, and cyclohexanone peroxide.

These radical initiators are also used as thickeners when low melting point rubber such as styrene isoprene rubber or liquid rubber such as 1,2-polybutadiene is used as a component for imparting fluidity. You can

The radical initiator can be used in the range of 0.5 to 5% by weight. It is preferably used in the range of 1 to 3% by weight.

In the present invention, a crosslinking aid can be used in addition to the radical initiator. Examples of the crosslinking aid include quinonedioxime-based, maleimide-based, methacrylic-based, allyl-based, and olefin-based agents. Specifically, p
-Quinone dioxime, p, p-dibenzoylquinone dioxime, lauryl methacrylate, ethylene glycol acrylate, triethylene glycol dimethacrylate, tetraethylene glycol dimethacrylate, polyethylene glycol dimethacrylate, trimethylol trimethylol propene trimeta Acrylate, methyl methacrylate, diallyl fumarate, diallyl phthalate, tetraallyloxyethane, triallyl cyanurate, maleimide, phenylmaleimide,
Examples thereof include N, N'-m-phenylmaleimide, divinylbenzene, and 1,2-polybutadiene having a double bond in the side chain.

Depending on the case, a vulcanization accelerator, a vulcanization acceleration aid, a filler, a reinforcing fiber and the like can be added if necessary.

Examples of the vulcanization accelerator include guanidine-based, thiazole-based, sulfenamide-based, thiuram-based, dithioate-based and thiourea-based compounds, and specific examples thereof include 2-mercaptobenzothiazole and dibenzothiazyldisulfide. , Cyclohexyl benzothiazyl disulfane amitite, N-oxydiethylene benzothiazyl-2-
Sulfane amite, Nt-butyl-2-benzothiazole Sulfane amite, 2- (thymolpolynyl dithio) benzothiazole, tetramethiuram disulfide, tetraethiuram disulfide, tetramethiuram monosulfide , Dipentamethylene thiuram tetrasulfide, Zn-dimethyl dithiocarbamate, Zn-diethyl dithiocarbamate, Zn
-Di-n-butyl dithiocarbamate, Zn-ethyl phenyl dithiocarbamate, Te-dimethyl
Examples thereof include dithiocarbamate, Cu-dimethyl dithiocarbamate, Fe-dimethyl dithiocarbamate, ethylene thiourea, and diethylthiourea.

Examples of vulcanization accelerators include zinc white, fatty acids such as stearic acid and oleic acid.

The reinforcing agent is for improving mechanical properties and is an organic / inorganic fiber such as glass fiber, carbon fiber, aramid fiber, alumina fiber or metal wire, which may be in the form of woven fabric, mat or chop, or resin. From the viewpoint of adhesion with, it is more preferable that the silane coupling agent has a radically polymerizable group and that the surface has irregularities.

As the filler, calcium carbonate,
Organic / inorganic powders such as diatomaceous earth and wood powder can be added according to the purpose.

In the present invention, the thermosetting resin powder may be a powder obtained by coating scraps such as runners and burrs produced in a molded product or molding process, and the powder is generally commercially available. It is easily obtained with a crusher. As for the particle size of the powder, those which have passed through a wire net of 5 to 400 mesh can be used, and those which have passed through a wire net of 30 to 300 mesh are particularly preferably used.

The composition of the present invention can be formed into a sheet-like structure and used for thermocompression molding. The sheet-like structure is a sheet-like structure in which both sides of a paste-like mixture consisting of a thermosetting resin powder having radically crosslinkable active hydrogen, a polymer component for imparting fluidity and a radical initiator are covered with films. It is the one. The sheet-shaped structure may further contain a thickener, a crosslinking aid, a vulcanization accelerator, a vulcanization accelerator aid, a filler, a reinforcing agent and the like. This is treated at a predetermined temperature for a certain period of time, thickened by a chemical reaction to make it tack-free, and then the film is peeled off for use. In the molding step, a so-called SMC molding method can be used in which a sheet-shaped structure that matches the shape of the molded product is pressure-cured and molded in a heated mold.

In the present invention, the preferable conditions for thermocompression molding depend on the type of resin, the type of radical initiator, and the presence of other additives, but generally the temperature is 70 to 200.
C., particularly in the range of 100 to 160.degree. C. is preferably used.
The pressure can be selected as well, but generally 10 to
200 kg / cm ^2, in particular in the range of 20 and 100 kg / cm ² is preferred. The hot pressing time can be selected in the same manner, but is generally in the range of 1 minute to 1 hour, preferably 3 minutes to 40 minutes.

Thus, by thermocompression molding, a molded product conforming to an arbitrary mold shape can be obtained.

[0039]

The molded product obtained by such thermocompression molding is considered to be because the polymer was further highly cross-linked by the radical initiator, but it was obtained as a homogeneous molded product, and compared with the original resin. Since the heat deformation temperature and the bending modulus are improved, it can be suitably used for applications requiring heat resistance and mechanical strength. Furthermore, the present invention has found the possibility of re-grinding these molded articles and recycling them any number of times using the present invention. . Further, the crosslinked polymer molded product of the present invention can exhibit a new function beyond the scope of simple recycling and can be used for a wide range of applications.

[0040]

EXAMPLES The present invention will be described in detail below with reference to examples and comparative examples. The examples are for purposes of illustration and not limitation.

(Resin powder used) Powders of hard polyurethane, unsaturated polyester containing 30% by weight of glass, and polydicyclopentadiene used in the examples are finer than 30 mesh obtained by crushing individual molded products with a commercially available crusher. Used as a powder. As the powder containing polydicyclopentadiene as a main raw material, Meton (registered trademark) manufactured by Teijin Hercules Co., Ltd., T-02, and a glass-reinforced S-RIM grade molded product were used.

[0042]

[Comparative Examples 1 to 6] The powders above 200 ° C, 50 kg / cm
^The molded product obtained by thermocompression molding under the condition of ² was brittle, and the physical properties could not be measured. Also, 250
It shows that a molded product can be obtained only when thermocompression molding is performed under a high temperature condition of ° C, and that molding conditions at a high temperature are required when a radical polymerization initiator is not added. In addition, it is shown that the surface of the molded product is rough in the heat compression molding of the powder, and further, it is necessary to add the polymer component agent which imparts fluidity because the molded product having a complicated shape cannot be molded. Table 1 shows molding conditions, heat resistance (heat deformation temperature when a load of 18.5 kg / cm ² was applied), bending strength, and bending modulus data.

[0043]

Examples 1 to 14 The above-mentioned resin pulverized product, radical initiator, crosslinking aid, polymer component for imparting fluidity, thickener,
The compositions of reinforcing agents, etc. are shown in Tables 2-4. When the reinforcing agent was used, a cloth roughly woven in a grid pattern was used.
Each composition was formed into a sheet by covering both sides of the paste with a film. Sheet-like structure at room temperature
Leave it for 3 days, thicken it by a chemical reaction to make it non-tacky, then peel off the film and press-cure the sheet-like structure according to the shape of the molded product into a heated mold to smooth the surface. A molded product was obtained. Figure 1 shows a schematic of the sheet-like structure.
It was shown to. Tables 2 to 4 show molding conditions and heat resistance (18.5 kg /
The data of heat deformation temperature under load of cm ² ), bending strength, and bending modulus are shown. By selecting the radical polymerization initiator, it is possible to select molding conditions that meet the respective molding temperature and time requirements, and the resulting molded product is simply a cross-linking reaction molding with higher heat resistance and bending modulus than the thermocompression molded product. It can be seen that this is a product and has new performance. In addition, a molded article having a smooth surface was obtained by adding a polymer component that imparts fluidity. Further, the sheet-like shape has significantly improved handling and facilitated molding of complicated shapes. It can be seen that the physical properties are significantly improved by the addition of the reinforcing agent.

In addition, Example 3 shows that not only the powders mixed with two or more kinds can be recycled but also the separation and collection can be simplified.

[0045]

Examples 15 to 17 In order to confirm recyclability, the above-mentioned molded product was pulverized again, and a sheet-like structure was prepared in the same manner. It was confirmed that this sheet-shaped structure can be molded under the same conditions as before, and there is no significant change in physical properties. (See Table 4) Therefore, it is shown that this molding method is a recyclable method.

[0046]

[Table 1]

[0047]

[Table 2]

[0048]

[Table 3]

[0049]

[Table 4]

[Brief description of drawings]

FIG. 1 shows an example of a sheet-shaped structure.

[Explanation of symbols]

1 a pulverized product, a radical initiator, a paste-like composition obtained by mixing a polymer component that imparts fluidity 2 a reinforcing agent 3 a polyethylene film

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Claims (8)

[Claims] 1. A crosslinked polymer molded article obtained by hot-pressing a composition comprising a thermosetting resin powder having active hydrogen capable of radical crosslinking, a polymer component imparting fluidity, and a radical initiator. Manufacturing method. 2. The method for producing a crosslinked polymer molded article according to claim 1, wherein the composition is further subjected to thermocompression molding with a reinforcing agent. 3. The method for producing a crosslinked polymer molded article according to claim 1, wherein the composition is made to further contain a thickener and hot-pressed. 4. A crosslinked polymer molded article obtained by the production method according to claim 1, 2. 5. A composition comprising a powder of a thermosetting resin having active hydrogen capable of radical crosslinking, a polymer component imparting fluidity and a radical initiator. 6. The composition according to claim 5, which further comprises a reinforcing agent. 7. The composition according to claim 5, further comprising a thickener. 8. A polymer component and a radical which impart fluidity when the powder of the crosslinked polymer molding according to claim 4 is reused as a powder of a thermosetting resin having active hydrogen capable of radical crosslinking. A method for producing a crosslinked polymer molded article, which comprises thermocompression molding with an initiator.