JPH0784035B2 - Fiber-reinforced resin molding and method for manufacturing the same - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a fiber-reinforced resin molded product and a method for producing the same, and more specifically to a matrix of a thermosetting polymer and lamination or embedding in this matrix. And a reinforcing layer of silane-crosslinked ultrahigh molecular weight polyethylene fibers, which has excellent mechanical properties such as high elastic modulus and high strength, and excellent electrical properties. The present invention also relates to a method of making the same.

(Prior Art) Japanese Patent Application Laid-Open No. 58-171951 discloses a network of ultrahigh molecular weight polyethylene fibers or polypropylene fibers, and a polyethylene crystal region or a polypropylene crystal region, which has a melting point or sticking point higher than that of the polyolefin fibers. At least 3 ° C
A composite structure consisting of a matrix composed of a low polymer is described, which shows a measured strength that is higher than the theoretical estimate, and the increase in the strength of this composite is caused by the loss of fiber crystallinity that occurs during molding. It is also stated that it is based on certain preferable effects which are more than supplementary to the above.

(Problems to be Solved by the Invention) Stretched fibers of ultra-high molecular weight polyethylene have a high elastic modulus and high tensile strength, but have the inherent drawback of polyethylene, that is, the poor heat resistance.

Generally, it is known that the heat resistance of polyolefin is improved by the molecular orientation of polyethylene or by the cross-linking of polyethylene, but there is a limit to the improvement of heat resistance in this conventional technique, and the melting point of polyethylene is 110 after all. To 140 ° C., which is a fundamentally unavoidable constraint of being in a relatively low range, and as far as the inventors of the present invention know, after exposing a molded body of polyethylene to a temperature of 180 ° C. for 10 minutes, Most of it melts and loses its strength.

Thus, polyolefin reinforced fibers are compound-cured at a temperature higher than their melting point with a thermosetting polymer monomer or prepolymer, such that the polyolefin-reinforced fibers are present in the composite structure in their original oriented crystallized state. The resin molding has not yet been known.

Therefore, an object of the present invention is to have a composite structure of a matrix of a thermosetting polymer and a reinforcing layer of polyolefin fibers laminated or embedded in the matrix, in which the polyolefin fibers are in an originally oriented crystalline state. The present invention is to provide a machine-cured resin molded body which is present and as a result is imparted with a remarkably high elastic modulus and mechanical strength, and a method for producing the same.

Another object of the present invention is to have a composite structure of a matrix of epoxy resin and molecular orientation and silane cross-linked ultra high molecular weight polyethylene fibers laminated or embedded in the matrix, and having high elastic modulus, high strength and impact resistance. Another object of the present invention is to provide a fiber-reinforced resin molded article having excellent mechanical properties such as creep resistance, light weight, and electrical characteristics, and a method for producing the same.

(Means for Solving the Problems) According to the present invention, a matrix of a thermosetting resin having a curing temperature of 220 ° C. or lower and a molecular orientation and a silane-crosslinked ultrahigh molecular weight polyethylene fiber laminated or embedded in the matrix are used. There is provided a fiber-reinforced resin molded product comprising at least one reinforcing layer, wherein the reinforcing layer substantially has an oriented crystal structure of ultrahigh molecular weight polyethylene fibers.

According to the present invention, a filament of molecular orientation and silane cross-linked ultra high molecular weight polyethylene, or a nonwoven fabric composed of this filament, a woven fabric or a knitted fabric is arranged in the plane direction and the end portions thereof are restrained, and the curing temperature is Provided is a method for producing a fiber-reinforced resin molded product, which comprises incorporating a monomer or a prepolymer of a thermosetting polymer at 220 ° C. or lower and curing it.

(Operation) The present invention, after binding the molecularly oriented silane crosslinked fiber of ultra-high molecular weight polyethylene under constrained conditions, after combining the monomer or prepolymer of the thermosetting polymer having a curing temperature of 220 ° C. or less into a composite structure, It is based on the novel finding that the oriented crystal structure of the fibers is substantially retained in the composite structure formed upon curing.

The reinforcing fiber used in the present invention is produced by molding a product obtained by grafting silanes on ultra-high molecular weight polyethylene, and stretching the molded product to perform silane crosslinking. It has a novel property that the melting point of at least a part of the polymer chains constituting this is remarkably improved under restraint conditions as compared with the original melting point of the raw material ultrahigh molecular weight polyethylene. Note that the constraint condition means that the fiber is not positively tensioned, but is, for example, a condition that the ends are fixed or that it is wrapped around another object such as a frame so as to prevent free deformation. Means

That is, the molecularly oriented silane crosslinked product of the ultrahigh molecular weight polyethylene used in the present invention is generally the crystalline fusion of the original ultrahigh molecular weight polyethylene obtained as the main melting peak of the second heating when measured by a differential scanning calorimeter in a restrained state. Temperature (Tm)
It has at least two crystal melting peaks (Tp) at a temperature higher by at least 10 ° C. than the above, and the heat of fusion based on this crystal melting peak (Tp) is 40% or more and the temperature range Tm + 35 ° C. to Tm + 120. It has a characteristic that the total amount of heat of fusion based on the high temperature side melting peak (Tp ₁ ) at 5 ° C. is 5% or more based on the total amount of heat of fusion.

The melting point of a polymer is associated with melting of crystals in the polymer and is generally measured as an endothermic peak temperature associated with melting of crystals in a differential scanning calorimeter. This endothermic peak temperature is
It is constant if the type of polymer is fixed, and it hardly changes due to subsequent treatment such as stretching treatment or cross-linking treatment. Only 15 ° C at most is moved to the high temperature side by heat treatment.

FIG. 1 of the accompanying drawings is an endothermic curve in a differential scanning calorimeter measured under constrained conditions of molecularly oriented silane crosslinked filament fibers of ultra high molecular weight polyethylene used in the present invention,
FIG. 2 is an endothermic curve of the raw material ultrahigh molecular weight polyethylene, FIG. 3 is an endothermic curve of the drawn filament of the ultrahigh molecular weight polyethylene of FIG. 2 also under restraint conditions, and FIG. 4 is FIG. 3 is an endothermic curve under restrained conditions of an unstretched filament obtained by subjecting the ultra-high molecular weight polyethylene of Example 1 to silane crosslinking. For details of raw materials and processing conditions, refer to the examples described later.

From these results, the mere stretched product or silane cross-linked product of ultra-high molecular weight polyethylene shows an endothermic peak associated with crystal melting at about 135 ° C, which is almost the same as that of untreated ultra-high molecular weight polyethylene. In contrast, the peak area (heat of fusion) is reduced in comparison with the peak area of the untreated one, whereas in the stretched crosslinked fiber used in the present invention, the melting peak temperature of the untreated ultra-high molecular weight polyethylene is It can be seen that the small peak remains, but the large peak shifts to a rather high temperature side.

FIG. 5 shows an endothermic curve when the sample of FIG. 1 was applied to a second run (the second temperature increase measurement after performing the measurement of FIG. 1). From the results of FIG. 5, the main peak of crystal melting appears at almost the same temperature as the melting peak temperature of untreated ultra-high molecular weight polyethylene in the case of reheating, and at the time of measurement in FIG. Since the orientation has almost disappeared,
The shift of the endothermic peak to the high temperature side in the sample of FIG.
It shows that it is closely related to the molecular orientation in the fiber.

The reason why the crystal melting temperature shifts to the high temperature side in the oriented crosslinked fiber used in the present invention has not yet been sufficiently clarified, but the present inventors presume the reason as follows. That is, when the silane-grafted ultra-high molecular weight polyethylene is subjected to a stretching operation, the silane-grafted portion selectively becomes an amorphous portion, and the oriented crystal portion is generated through this amorphous portion. Next, when this drawn fiber is crosslinked in the presence of a silanol condensation catalyst, a crosslinked structure is selectively formed in the amorphous part, and both ends of the oriented crystal part are fixed by silane crosslinking. In a normal stretched fiber, crystal melting proceeds from the amorphous part at both ends of the oriented crystal part, whereas in the stretched crosslinked fiber used in the present invention, the amorphous part at both ends of the oriented crystal part is selectively cross-linked to produce heavy polymer. It is considered that the melting temperature of the oriented crystal part is improved because the united chains are hard to move.

In the molecularly oriented silane crosslinked fiber of ultra-high molecular weight polyethylene used in the present invention, not only the fiber form but also the oriented crystal form is maintained even at a temperature higher than the original melting point of the polyethylene. Machines such as tensile strength, flexural strength, elastic modulus, impact resistance, etc., after being laminated or embedded in a thermosetting polymer monomer or prepolymer with a curing temperature of 220 ° C or less under restraint conditions and then cured. It is possible to obtain a fiber-reinforced resin molded product having excellent physical properties.

Particularly, in the present invention, it is possible to obtain a fiber-reinforced resin molded product with a thermosetting polymer having a curing temperature of higher than 150 ° C., which is completely impossible with conventional polyethylene fibers.

(Explanation of Preferred Embodiment) Fiber-Reinforced Resin Molded Product In FIG. 6 showing an example of the fiber-reinforced resin molded product of the present invention, this molded product 1 comprises a matrix 2 of a thermosetting polymer having a curing temperature of 220 ° C. or lower, and It consists of a reinforcing layer 3 of molecularly oriented and silane-crosslinked ultra high molecular weight polyethylene fibers embedded in or laminated with the matrix 2. The fiber reinforcing layer 3 may be provided as a single layer or a multilayer including two or more layers. In the embodiment shown in FIG. 6, the fiber-reinforced layer 3 is completely embedded in the matrix of the thermosetting polymer, and both surfaces 4a, 4b of the shaped body consist essentially of the thermosetting polymer. However, as shown in the specific example of FIG. 7, the fiber reinforcing layer 3 is integrally laminated with the thermosetting polymer matrix and is present on one or both of the surfaces 4a and 4b or in the vicinity thereof. Good.

In the fiber-reinforced resin molded product of the present invention, the ultrahigh molecular weight polyethylene fibers forming the fiber-reinforced layer 3 substantially have the oriented crystal structure. This reinforcing layer 3 is embedded or laminated over the entire surface of the molded body 1, and is a filament of molecular orientation and silane-crosslinked ultra high molecular weight polyethylene oriented in at least one axial direction of the molded body 1, or a nonwoven fabric or woven fabric made of this filament. Consists of a composition or composition.

The proportion of the fiber-reinforced layer and the thermosetting polymer matrix varies considerably depending on the application, thickness, etc., but generally speaking, the fiber-reinforced layer accounts for 20 to 80% by volume, especially 40% by volume.
It is desirable to be present in such a proportion that it occupies 70% by volume.

When the volume ratio of the fiber reinforced layer is less than the above range, tensile strength, bending strength, elastic modulus, impact resistance, creep resistance, etc. are not sufficiently improved by fiber reinforcement, and the volume ratio exceeds the above range. If the number increases, it tends to be difficult to form an integrated fiber-reinforced resin molded product.

Reinforcing Layer The molecular orientation and silane-crosslinked ultrahigh molecular weight polyethylene fiber used in the present invention are thermoforming a composition containing an ultrahigh molecular weight polyethylene having an intrinsic viscosity [η] of 5 dl / g or more, a silane compound, a radical initiator and a diluent. Then, the silane compound-grafted ultra-high molecular weight polyethylene molded product is stretched, and a silanol condensation catalyst is impregnated into the stretched molded product of the molded product during or after stretching, and then the stretched molded product is contacted with water. It is manufactured by cross-linking.

Ultra high molecular weight polyethylene (A) is a decalin solvent 135
Intrinsic viscosity at ℃ [η] is 5dl / g or more, preferably 7
To 30 dl / g.

Such ultra-high molecular weight polyethylene is obtained by polymerizing ethylene or ethylene and a small amount of other α-olefin such as propylene, 1-butene, 4-methyl-1-pentene, 1-hexene by so-called Ziegler polymerization. The polyethylene obtained has a much higher molecular weight.

On the other hand, as the silane compound used for the graft treatment,
Any silane compound that can be grafted and crosslinked can be used, and such a silane compound has both a radical-polymerizable organic group and a hydrolyzable organic group. General formula RnSiY _4-n (1) In the formula, R is an organic group containing radically polymerizable ethylenic unsaturation, Y is a hydrolyzable organic group, and n is a number of 1 or 2. It is represented by.

As the radically polymerizable organic group, a vinyl group, an allyl group,
Butenyl group, an ethylenically unsaturated hydrocarbon group such as cyclohexenyl group, an acryloxyalkyl group, an alkyl group containing an ethylenically unsaturated carboxylic acid ester unit such as a methacryloxyalkyl group, and the like, vinyl Groups are preferred. Examples of the hydrolyzable organic group include an alkoxy group and an acyloxy group.

Suitable examples of silane compounds include, but are not limited to, vinyltriethoxysilane, vinyltrimethoxysilane,
Vinyl tris (methoxyethoxy) silane and the like.

First, silane graft molding is performed by thermoforming a composition containing the above-mentioned ultrahigh molecular weight polyethylene, a silane compound, a radical initiator and a diluent by melt extrusion or the like.
That is, the radical causes grafting of the silane compound onto the ultrahigh molecular weight polyethylene.

As radical initiators, all radical initiators used in this type of grafting process can be used, such as organic peroxides, organic peresters, tyronitrile, dimethylazoisobutyrate. In order to effectively perform grafting under the melt-kneading condition of ultra high molecular weight polyethylene,
The half-life temperature of the radical initiator is preferably in the range of 100 to 200 ° C.

A diluent is included with the above components to enable melt molding of silane-grafted ultra high molecular weight polyethylene. As such a diluting agent, a solvent for ultra-high molecular weight polyethylene and various wax-like substances having compatibility with ultra-high molecular weight polyethylene are used.

The silane compound is 0.1 to 10 parts by weight, particularly 0.2 to 5.0 parts by weight, and the radical initiator is a catalytic amount, generally 0.01 to 3.0 parts by weight, and particularly 0.0 per 100 parts by weight of the ultra high molecular weight polyethylene.
5 to 0.5 parts by weight and diluent 9900 to 33 parts by weight, especially 19
It is preferably used in an amount of 00 to 100 parts by weight.

Melt kneading is generally carried out at a temperature of 150 to 300 ° C., particularly 170 to 270 ° C., and the compounding is carried out by a Henschel mixer,
It may be performed by dry blending using a V-type blender or the like, or may be performed by melt mixing using a single-screw or other-screw extruder.

The molten mixture is extruded through a spinneret and shaped into filaments. In this case, the melt extruded by the spinneret can be drafted, that is, stretched in a molten state. Extrusion speed of molten resin in die orifice V ₀
The draft ratio can be defined by the following equation as a ratio of the winding speed V of the unstretched and solidified by cooling.

Draft ratio = V / V ₀ (2) The draft ratio depends on the temperature of the mixture, the molecular weight of the ultrahigh molecular weight polyethylene, etc., but is usually 3 or more, preferably 6
The above can be done.

The resulting unstretched filament is stretched.

The stretching of the silane-grafted polyethylene filament is preferably carried out at a temperature of generally 40 to 160 ° C, especially 80 to 145 ° C. As the heat medium for heating and holding the unstretched filament at the above temperature, any of air, water vapor and liquid medium can be used. However, as the heat medium, a solvent capable of eluting and removing the above-mentioned diluent and having a boiling point higher than the melting point of the molding composition,
Specifically, decalin, decane, kerosene or the like is used to carry out a stretching operation, whereby the above-mentioned diluent can be removed, and at the same time, uneven stretching such as stretching can be eliminated and a high stretching ratio can be achieved. .

The stretching operation can be performed in one stage or in multiple stages of two or more stages. Although the draw ratio depends on the desired molecular orientation effect, satisfactory results can be obtained by carrying out the draw operation so that the draw ratio is generally 5 to 80 times, particularly 10 to 50 times.

During or after the stretching, the molded product is impregnated with a silanol condensation catalyst, and then the stretched molded product is brought into contact with water to crosslink.

As the silanol condensation catalyst, use can be made of ones known per se, for example, dialkyltin dicarboxylates such as dibutyltin dilaurate, dibutyltin diacetate, dibutyltin dioctoate; organic titanates such as tetrabutyl titanate; lead naphthenate and the like. You can These silanol condensation catalysts can be effectively impregnated into these molded products by bringing them into contact with an unstretched molded product or a stretched molded product while being dissolved in a liquid medium. For example, when the stretching treatment is carried out in a liquid medium, the silanol condensation catalyst should be dissolved in the stretching liquid medium so that the molding operation of the silanol condensation catalyst is performed at the same time as the stretching operation. You can

The amount of the silanol condensation catalyst to be impregnated in the molded body may be a so-called catalytic amount, and it is difficult to directly specify the amount, but in general, it is in an unstretched or drawing agent contacting the molded body in a liquid medium. 10 to 100% by weight, especially 25 to 75% by weight
A satisfactory result is obtained by adding the silanol condensation catalyst in an amount of 10 and contacting the liquid medium with the filament.

The cross-linking treatment of the stretched molded product is performed by bringing the stretched molded product of the silane-grafted ultrahigh molecular weight polyethylene impregnated with the silanol condensation catalyst into contact with water. As the conditions for the crosslinking treatment, it is advantageous to bring the stretched molded product into contact with water at a temperature of 50 to 130 ° C. for 3 to 24 hours. For this purpose, water is preferably applied to the stretch-molded product in the form of hot water or hot steam. At the time of this cross-linking treatment, the stretched molded article may be placed under restrained conditions to prevent orientation relaxation, or conversely, some degree of orientation relaxation may occur under unconstrained conditions.

In addition, mechanical strength such as tensile strength is further improved by further performing a stretching treatment (usually 3 times or less) after the stretched molded body is crosslinked.

The molecular orientation and silane-crosslinked ultrahigh molecular weight polyethylene fibers used in the present invention have a crystal melting peak (Tp) at a much higher temperature than the original crystal melting temperature (Tm) of the ultrahigh molecular weight polyethylene under constrained conditions. It has the surprising feature of showing.

The original crystal melting temperature (Tm) of ultra high molecular weight polyethylene is
This fiber can be obtained by once melting the fiber once, relaxing the molecular orientation in the molded body, and then raising the temperature again, that is, a second run in a so-called differential scanning calorimeter.

As is apparent from FIG. 1 described above, the filament used in the present invention has at least two crystal melting peaks (Tp) at a temperature which is at least 10 ° C. higher than the original crystal melting temperature (Tm) of ultrahigh molecular weight polyethylene. And the heat of fusion based on the crystal melting peak (Tp) per heat of pre-fusion is 40% or more, particularly 60% or more.

In general, the crystal melting peak (Tp) of the fiber used in the present invention includes a high temperature side melting peak (Tp ₁ ) in the temperature range Tm + 35 ° C. to Tm + 120 ° C. and a warming range Tm + 10 ° C. to Tm + 35 ° C.
It often appears as a low-temperature side peak (Tp ₂ ) in ₂ ), and the melting peak of Tm itself is extremely small.

The high temperature side melting part (Tp ₁ ) is related to the silane grafting amount of the molded product, and when the silane grafting amount is small, a clear maximum point (peak) does not appear in the melting curve and a broad maximum point (peak). Or T on the high temperature side of the low temperature side melting part (Tp ₂ ).
It often appears as a shoulder or skirt from m + 35 ℃ to Tm + 120 ℃.

In addition, when the melting peak of Tm is extremely small, it may not be visible because it is hidden by the shoulder of the melting peak of Tp ₁ . If Tm
Even if there is no melting peak of, there is no problem in the function of the ultra high molecular weight polyethylene filament. Tm + 35 ℃ ~ Tm
High temperature side melting peak (Tp ₁ ) at + 120 ℃ and temperature range Tm
The low temperature side melting peak (Tp ₂ ) at + 10 ° C. to Tm + 35 ° C. may be further divided into two or more melting peaks depending on the sample preparation conditions and the melting point measurement conditions.

These high crystal melting peaks (Tp ₁ , Tp ₂ ) act to significantly improve the heat resistance of ultra-high molecular weight polyethylene filaments, but contribute to the improvement of the strength retention rate after high temperature thermal history. Is the melting peak on the high temperature side (T
p ₁ ).

Therefore, the total amount of heat of fusion based on the high temperature side melting peak (Tp ₁ ) in the temperature range Tm + 35 ° C. to Tm + 120 ° C. is preferably 5% or more, particularly 10% or more, based on the previous amount of heat of fusion.

In addition, as long as the total amount of heat of fusion based on the high temperature side melting peak (Tp ₁ ) satisfies the above value, if the high temperature side melting peak (Tp ₁ ) does not appear as a major peak, that is, a small peak. Even if the aggregate of the above or a broad peak occurs, the heat resistance may be slightly lost, but the creep resistance is excellent.

The degree of molecular orientation in the molded body can be known by an X-ray diffraction method, a birefringence method, a fluorescence polarization method, or the like. In the case of the drawn silane cross-linked filament used in the present invention, for example, Yuki Kure and Teruichiro Kubo: Industrial Chemistry Journal, Vol. 39, p. In the formula, H ° is the half value (°) of the intensity distribution curve along the Debye ring of the strongest paratropic plane on the equator line.

It is desirable from the viewpoint of heat resistance and mechanical properties that the molecular orientation is such that the degree of orientation (F) defined by is 0.90 or more, particularly 0.95 or more.

In addition, the grafting amount of silane is 135 ° C.
It can be determined by carrying out an extraction treatment in p-xylene for 4 hours at the above temperature to extract and remove unreacted silane and the contained diluent, and quantify Si by a gravimetric method or an atomic absorption method. The silane graft amount of the fibers used in the present invention is preferably 0.01 to 5% by weight, particularly 0.035 to 3.5% by weight, expressed as Si weight per ultra high molecular weight polyethylene, from the viewpoint of heat resistance. That is, when the grafting amount is less than the above range, the crosslink density is smaller than that of the present invention, while when it is more than the above range, the crystallinity decreases and the heat resistance is insufficient in any case. Becomes

In the molecular orientation-silane cross-linked fiber used in the present invention, since the crystal melting temperature of at least a part of the polymer chains constituting the fiber is shifted to the extremely high temperature side as described above, it is extremely excellent in heat resistance. , The strength retention rate after applying heat history at 160 ℃ for 10 minutes is 80% or more, preferably 180 ℃
The strength retention rate after applying a heat history of 10 minutes at 60 ° C or more, especially 80% or more, and the strength retention rate after applying a heat history of 5 minutes at 200 ° C is 80% or more. That is, it shows surprising heat resistance that cannot be expected from conventional ultra high molecular weight polyethylene.

The filament used in the present invention has a heat-resistant creep property,
For example, under the conditions of load: 30% breaking load, temperature: 70 ° C., the uncrosslinked filament shows an elongation of 50% or more after being left for 1 minute, while the filament is extremely excellent at 30% or less, further 20% or less. There is.

Further, the filament used in the present invention is further subjected to a load of 50% breaking load and a temperature of 70 ° C. for the uncrosslinked material to undergo elongational elongation without waiting 1 minute, whereas Elongation is 20% or less.

Moreover, since this molded product contains grafted and crosslinked silanes, it has excellent adhesiveness, particularly adhesiveness with various resins, and this fact can be easily understood by referring to the examples described later. Be understood by.

Furthermore, this filament is made of ultra-high molecular weight polyethylene, and since it is effectively imparted with molecular orientation, it is also excellent in mechanical properties.For example, the elastic modulus of 20 GPa or more and 1.2 GPa or more in the form of a drawn filament. Indicates tensile strength.

The fineness of the monofilament of the molecularly oriented silane crosslinked filament is not particularly limited, but from the viewpoint of strength, it is generally desired to be in the range of 0.5 to 20 denier, especially 1 to 10 denier.

This filament is generally used as a fiber reinforcing layer for a thermoplastic resin in the form of multifilament, multifilament plied yarn, non-woven fabric, woven fabric or knitted fabric made of these.

Polymer Matrix The thermosetting polymer for the matrix used in the present invention must have a monomer or prepolymer curing temperature of 220 ° C. or lower. If the curing temperature exceeds 200 ° C,
The molecularly oriented and silane-crosslinked ultrahigh molecular weight polyethylene fibers incorporated into the fiber-reinforced resin molding become substantially devoid of its oriented crystal structure. The matrix thermosetting polymer used is preferably 100 to 200 ° C., particularly 150 to 180 ° C.
Those having a curing temperature of 0.degree. C. are desirable.

Preferable examples of such thermosetting polymer for matrix include phenol resin, furan resin, xylene formaldehyde resin, ketone / formaldehyde resin, urea resin, melamine resin, aniline resin, alkyd resin, unsaturated polyester resin, diallyl phthalate. Examples thereof include resins, epoxy resins, triallyl cyanurate resins, triazine resins, polyurethanes, and silicone resins.

One of these thermosetting resins is preferably an epoxy resin, such as bisphenol A type epoxy resin, bisphenol F type epoxy resin, phenol novolac type epoxy resin, cresol novolac type epoxy resin, alicyclic epoxy resin, Heterocyclic epoxy resins such as triglycidyl isocyanate and hydantoin epoxy, hydrogenated bisphenol A type epoxy resins, aliphatic epoxy resins such as propylene glycol diglycidyl ether and pentaerythritol polyglycidyl ether, aliphatic or aromatic carboxylic acids Of glycidyl ether type epoxy resin, which is a reaction product of an epoxy resin, a spiro-ring-containing epoxy resin, an o-allylphenol novolac compound, and epichlorohydrin obtained by the reaction of epichlorohydrin with Carboxymethyl resins, diallyl bis phenol compound and a glycidyl ether type epoxy resin is the reaction product of epichlorohydrin with allyl groups in the o- for each hydroxyl group of the bisphenol A is used.

And these epoxy resins have an epoxy equivalent of about 70.
-3300, preferably about 100-1000, softening point (by Duran method) of about 60-150 ° C, preferably about 65-95 ° C, and viscosity (25 ° C) of about 10-30000 cps, preferably about 1000-15.
The one of 000 cps is generally used.

As a matter of course, when an epoxy resin is used, a curing agent known for it, for example, boron trifluoride amine complex, tertiary amine, quaternary ammonium salt, borate compound, imidazole compound, metal Generally, a salt compound, an amide compound, a urea compound, a melamine compound, an isocyanate compound, a cyanate compound, a phenol compound, an aromatic or aliphatic amine compound, an acid anhydride, a polyamine compound and the like are used together.

Other suitable thermosetting resins include phenol resins obtained by the reaction of phenols and aliphatic aldehydes, which include a resole resin and an acid obtained by an alkali-catalyzed condensation reaction. And a novolac resin obtained by a condensation reaction using as a catalyst. The former is generally in liquid or paste form,
It is suitable for curing after compounding other components, and it is important for the latter to keep the reaction in a prepolymer state by sufficiently controlling the reaction. These phenolic resins have a viscosity (25 ° C) of about 100 to 10,000 cps, preferably about 200 to 5,000.
cps, softening point of about 50-150 ℃, preferably about 70-110
Those at ℃ are generally used.

As the curing agent for the novolac type phenolic resin, hexamine, paraformaldehyde, resole type phenolic resin and the like, which are also commonly used, are used.

Polyamines as also the polyimide resin is preferred one thermosetting resin, the general formula R- (NH _{2) n} [where R is a divalent organic radical, n is the a is an integer of 2 or more] represented by And the general formula [Wherein A is an organic group having at least 2 carbon atoms and m is 2-4], or a mixture thereof with an unsaturated bismaleimide or a pre-reactant thereof.

Examples of polyamines include hexamethylenediamine,
p-phenylenediamine, 44'-diaminodiphenylmethane, 4,4'-diaminodiphenyl ether, 4,4'-diaminodiphenyl ketone, 4,4'-diaminodiphenyl sulfone, xylylenediamine and the like. Examples of unsaturated bismaleimides include N, N'-phenylene bismaleimide, N, N'-hexamethylene bismaleimide N, N'-methylene-di-p-phenylene bismaleimide, N, N'- Oxy-di-p-phenylene bismaleimide, N, N'-4,4'-benzophenone bismaleimide, N, N'-p-diphenylsulfone maleimide, N,
N '-(3,3'-dimethyl) -methylene-di-p-phenylene bismaleimide, N, N'-4,4'-dicyclohexylmethane bismaleimide, N, N'-m (or p) -xylyl Renbismaleimide, N, N '-(3,3'-diethyl) methylene-di-p-phenylene bismaleimide, N, N'-
m-toluylene dimaleimide and the like, and these unsaturated bismaleimides are monomaleimide compounds such as N-allylmaleimide, N-propylmaleimide, N-hexylmaleimide, and N-phenylmaleimide at 60% by weight.
It can be replaced to some extent and used.

The polyimide resin prepared from each of these components can also be used in combination with the above-mentioned various epoxy resins or epoxy group-containing vinyl monomers such as glycidyl acrylate, glycidyl methacrylate and allyl glycidyl ether.

In addition, as an unsaturated polyester resin which is one of the preferable thermosetting resins, for example, (a) a reaction product of a polyol and a polycarboxylic acid, which is α,
An unsaturated polyester resin having a β-unsaturated bond and an acid value of 25 or less, (b) styrene, divinylbenzene, α
A vinyl monomer copolymerizable with an unsaturated polyester resin such as methylstyrene, alkyl (meth) acrylate, ethylene glycol di (meth) acrylate, (c)
Examples include a radical polymerization initiator such as dicumyl peroxide and benzoyl peroxide, and (d) a composition composed of components of an accelerator such as cobalt naphthenate, which is optionally used.

The thermosetting polymer matrix used in the present invention may include compounding agents known per se, such as lubricants / release agents, antioxidants, softeners / plasticizers, fillers, colorants, foaming agents, cross-linking agents, etc. One kind or two or more kinds can be blended according to a known formulation.

Manufacturing method The molded product of the present invention, in a state in which the fiber reinforced layers of various forms described above are arranged in the plane direction and the ends thereof are constrained,
It is produced by incorporating the above-mentioned thermosetting polymer monomer or prepolymer and then curing.

The combined curing of the fiber-reinforced layer and the thermosetting polymer monomer or prepolymer can be carried out by various methods. For example,
The pre-cured film or sheet of the pre-cured semi-cured B-stage and the fiber reinforcing layer are superposed to cure the pre-polymer of thermosetting polymer, but the ultra high molecular weight polyethylene fiber in the reinforcing layer This stack is pressure-bonded and cured at a temperature at which the oriented crystal structure of is substantially maintained. This pressure bonding operation may be performed by a batch operation or a semi-continuous operation like a hot press, or continuously like a hot roll press. At the time of this crimping operation, it is important that the end portion of the fiber reinforcing layer is restrained,
This can be achieved, for example, by pre-winding the fibers around the pressing substrate to restrain the ends, or by applying an appropriate tension to the fiber reinforcing layer during the crimping operation. When the fibers are arranged in the machine longitudinal direction and the direction perpendicular to the machine direction, tension may be applied in both directions so as not to allow free shrinkage of the fibers.

Alternatively, after impregnating the fiber-reinforced layer with the thermosetting polymer monomer or prepolymer, the thermosetting polymer monomer or prepolymer cures, but the orientation of the ultra high molecular weight polyethylene fibers in the reinforcement layer is increased. The impregnated fiber-reinforced layer is pressure-hardened in a single layer or in multiple layers at a temperature at which the crystal structure is substantially maintained.

The fiber-reinforced resin molded product according to the present invention is not limited to a two-dimensional shape. For example, the fiber-reinforced layer is arranged in a tubular shape in the form of filament or a nonwoven fabric, woven material or knitted material of the filament, and after coating or impregnating with a monomer or prepolymer of a thermosetting polymer, it is cured. A tubular fiber-reinforced resin molding is obtained. In addition, when the above molding method is applied with an electric wire or an optical cable as the core,
It is possible to form a sheath of a fiber-reinforced molded body.

(Effect of the Invention) According to the present invention, molecular orientation and silane-crosslinked ultrahigh molecular weight polyethylene fibers are combined with a monomer or prepolymer of a thermosetting polymer under restrained conditions and then cured to be integrated. As a result, the oriented matrix structure of the fibers can be present in the matrix of the polymer as a fiber reinforcing layer.

Therefore, this molded article is endowed with the excellent tensile properties of the fiber, and because the fiber is silane-modified, it has excellent adhesiveness with the thermosetting polymer, and thus has a high elastic modulus. A high-strength molded product can be obtained.

(Examples) Next, the present invention will be described more specifically with reference to Examples.
The present invention is not limited to these examples unless it exceeds the gist.

Example 1. <Preparation of silane crosslinked stretched ultra high molecular weight polyethylene fiber> Grafted and spun ultra high molecular weight polyethylene (intrinsic viscosity [η] = 8.20 dl / g)
Powder: 100 parts by weight of vinyltrimethoxysilane (manufactured by Shin-Etsu Chemical): 10 parts by weight and 2,5-dimethyl-2,5-di (tert-butylperoxy) hexane (manufactured by NOF CORPORATION: trade name, Perhexa) 25B): After uniformly blending 0.1 part by weight, powder of paraffin wax (made by Nippon Seiro Co., Ltd., trade name, Lubax) to 100 parts by weight of ultra high molecular weight polyethylene.
(1266, melting point = 69 ° C.): 370 parts by weight were added and mixed to obtain a mating product. Then, the mixture was melt-kneaded at a preset temperature of 200 ° C. using a screw type extruder (screw diameter = 20 mmφ, L / D = 25), and subsequently the melt was orifice diameter 2 mm.
The silane grafting was completed by spinning from the die. The spun fiber was cooled and solidified with air at room temperature in an air gap of 180 cm to obtain an unstretched ultra high molecular weight polyethylene silane graft fiber. The undrawn yarn had a denier of 800 and the draft ratio during spinning was 36.4. The winding speed at this time was 90 m / min.

Quantification of the amount of silane grafted About 8 g of unstretched graft fiber prepared by the above method
It was dissolved in 200 cc of p-xylene heated and kept at ℃. Then, ultra-high molecular weight polyethylene was precipitated in excess hexane at room temperature to remove paraffin wax and unreacted silane compound. After that, the graft amount determined by the gravimetric method as Si wt% was 0.57 wt%.

Stretching The grafted unstretched fiber spun from the ultra high molecular weight polyethylene mixture by the above method was stretched under the following conditions to obtain oriented stretched fiber. Two-stage drawing was performed in a drawing tank using n-decane as a heating medium using three godet rolls. At this time, the temperature in the first drawing tank was 110 ° C, the temperature in the second drawing tank was 120 ° C, and the effective length of the tank was 50 cm. In drawing, the rotation speed of the first godet roll was set to 0.5 m / min and the rotation speed of the third godet roll was changed to obtain a fiber having a desired draw ratio. Further, the rotation speed of the second godet roll was appropriately selected within a range in which stable stretching was possible. However, the stretching ratio was calculated and calculated from the rotation ratio of the first godet roll and the third godet roll.

The obtained fiber was dried at room temperature under low pressure to obtain a stretched ultra high molecular weight polyethylene silane graft fiber.

Impregnation of Crosslinking Catalyst When the oriented fiber of the silane compound-grafted ultrahigh molecular weight polyethylene prepared by the above method is further crosslinked, n-decane and dibutyltin in the same amount as n-decane are used as a heating medium in the second stretching tank during stretching. A mixture of dilaurates was used to extract the paraffin wax and simultaneously impregnate the fibers with dibutyl tin dilaurate. The obtained fiber was dried under reduced pressure at room temperature until the smell of decane disappeared.

Crosslinking After this, the fibers were left in boiling water for 12 hours to complete the crosslinking.

Measurement of gel fraction About 0.4 g of the silane-crosslinked stretched ultrahigh molecular weight polyethylene fiber obtained by the above method was placed in an Erlenmeyer flask equipped with a condenser containing 200 ml of paraxylene, and stirred in the boiling state for 4 hours. Then insoluble material made of stainless steel 300 m
I passed by the mesh of esh. After drying under reduced pressure at 80 ° C., the weight was measured and the weight of the insoluble matter was determined. The gel fraction was calculated by the following formula.

The gel fraction of the above prepared sample was 51.4%.

Tensile elastic modulus, tensile strength and elongation at break were measured using an Instron universal testing machine Model 1123 (manufactured by Instron) at room temperature (23
(° C). The sample length between the clamps was 100 mm and the tensile speed was 100 mm / min. However, the tensile modulus is the initial modulus. The fiber cross-sectional area required for the calculation was obtained by measuring the weight and length of the fiber with the density of polyethylene being 0.96 g / cm ³ .

Table 1 shows the physical properties of the silane-crosslinked stretched ultrahigh molecular weight polyethylene fiber thus obtained.

The crystal melting temperature (Tm) of the ultrahigh molecular weight polyethylene, which is the main melting peak during the second heating, is 132.2.
The ratio of the heat of fusion based on Tp to the heat of fusion of all crystals and the ratio of the heat of fusion based on Tp ₁ to the heat of fusion of all crystals were 73% and 22%, respectively. At this time Tp
Majority of ₂ is 151.0 ℃, majority of Tp ₁ is 22
It was 6.5 ° C.

Evaluation of Creep Properties The creep test was performed using a thermal stress strain measuring device TMA / SS10 (manufactured by Seiko Electronics Co., Ltd.) at a sample length of 1 cm and an ambient temperature of 70 ° C. Eighth result at 30% of breaking load
Shown in the figure. The silane-crosslinked stretched ultrahigh molecular weight polyethylene fiber (Sample-1) prepared in this Example is the stretched ultrahigh molecular weight polyethylene fiber (Sample-2) prepared in Comparative Example 1 described later.
In each case, it can be seen that the creep characteristics are remarkably improved.

At an ambient temperature of 70 ° C, 50% of the breaking load at room temperature
In a creep test conducted under a load equivalent to%, Table 2 shows the elongations 1 minute, 2 minutes, and 3 minutes after the loading.

Strength retention rate after heat history The heat history test was performed by leaving it in a gear open (perfect open: manufactured by Tabai Seisakusho). The sample was fixed to both ends of the sample by folding it back to a stainless frame having a plurality of pulleys at both ends and having a length of about 3 m. At this time, both ends of the sample were fixed so that the sample did not sag, and no tension was positively applied to the sample. The results are shown in Table 3.
Shown in.

From Table 3, it can be seen that the silane-crosslinked stretched upper molecular weight polyethylene fiber used in this example has a surprising heat resistance retention property.

Measurement of degree of orientation by X-ray diffraction The fibers were wound around a Phillips type holder 10 to 20 times, one side was cut off, and the fibers were bundled for measurement. The degree of orientation was obtained by measuring the (110) plane reflection of the polyethylene crystal appearing on the equator line with a diffractometer to obtain the reflection intensity distribution. The calculation followed the method of Kure et al. The degree of orientation thus obtained was 0.955.

<Molding of fiber reinforced resin molding> Epoxy resin (Mitsui Petrochemical, trade name = Epomic R
-301) 100g, same (manufactured by the same company, trade name = Epomic R-14)
0) 30 g, disiamine diamide 4 g, and N- (3,4-dichlorophenyl) -N ', N'-dinacyl urea 3 g, natyl ethyl ketone 33 g and N, N-dinatylformamide 20 g
A varnish was prepared by dissolving the varnish in the mixed solution. The silane cross-linked stretched polyethylene fiber wound around a stainless steel frame and fixed was impregnated with the above varnish and dried at 100 ° C. for 20 minutes to obtain a unidirectional prepreg. Next, nine prepregs thus obtained were stacked alternately, the periphery of each side was fixed with a metal frame, and press-molded at 160 ° C. for 6 minutes to prepare a 9-ply laminated plate. The content of silane-crosslinked stretched ultra high molecular weight polyethylene fibers in the obtained laminate was 58.0% by volume.

The bending elastic modulus and bending strength of the laminated plate were measured at room temperature (23 ° C) using an Instron universal testing machine type 1123 (manufactured by Instron).
In accordance with JIS K 6911 (ASTM D 790). The test piece sample at this time was 50 mm × so that the laminated plate was orthogonal to the fiber.
A 25 mm rectangular shape was cut and prepared. Table 4 shows the bending strength and the image elastic modulus of the obtained sample.

Tensile yield strength and tensile modulus are JIS K 6760 (ASTM D 638-
68). However, at this time, the sample piece sample is
It was prepared by punching the above laminated plate with a JIS No. 2 dumbbell. The results are shown in Table 5.

Comparative Example 1. Preparation of Ultra High Molecular Weight Polyethylene Stretched Fibers Ultra high molecular weight polyethylene (powder with intrinsic viscosity [η] = 8.20: 100 parts by weight and paraffin wax powder described in Example 1: 320 parts by weight) It was spun by the method described in 1.
At this time, the draft ratio was 25 times and the undrawn yarn fineness was 1000 denier. Then, it was similarly stretched to obtain a stretched fiber. Table 6 shows the physical properties of the obtained fibers.

The melting characteristic curve of this fiber (Sample-2) is shown in FIG.

The original crystal melting temperature Tm found as the main melting peak during the second heating is 132.2 ° C, and the ratio of the heat of fusion based on Tp to the total heat of fusion of the crystal and the ratio of the heat of fusion based on Tp ₁ to the heat of total crystal fusion are , 32.1% and 1. respectively.
It was 7%.

The creep characteristics were measured by the method described in the section <Evaluation of creep characteristics> in Example 1. The results are shown in Fig. 8.

Further, in the measurement of creep properties (atmosphere temperature = 70 ° C., load = 50% load of the breaking load at room temperature) performed in the same manner as the method described in Example 1, the sample ruptured immediately after the loading.

The adhesive strength was measured by the method described in the section <Evaluation of adhesiveness> of Example 1. The results are shown in FIG. 9 together with Example 1.

The strength retention rate after heat history was measured by the method described in the section of <strength retention rate after heat history> in Example 1, but the oven temperature was 180 ° C. Melted.

<Molding of Fiber Reinforced Resin Molded Product> Using the epoxy resin described in Example 1 as a matrix-soluble resin and the above-described ultrahigh molecular weight polyethylene stretched fiber, a unidirectional prepreg is obtained by the method described in Example 1. It was Then, the obtained prepregs were laminated alternately, and an attempt was made to prepare a laminated plate under the same conditions as in Example 1.
After cooling, when the inside of the molded body was visually observed, the fibers were melted and the fiber shape was lost.

Example 2 <Molding of Fiber Reinforced Resin Molded Product> An unsaturated polyester resin (manufactured by Showa Polymer Co., Ltd., product name = Rigolac 150H) was wound around and fixed on the stainless metal frame with the silane crosslinked stretched polyethylene fiber described in Example 1.
R) 100g, benzoyl peroxide 0.5g, cobalt naphthenate
A composition consisting of 0.5 g and 2 g of magnesium oxide was impregnated and press-molded at room temperature to obtain a unidirectional prepreg. After that, 9 sheets of the obtained prepreg are alternately laminated, the periphery of each side is fixed with a metal frame, and press molding is performed at 160 ° C. for 6 minutes,
A 9-ply laminate was prepared. The content of the silane crosslinked stretched ultra high molecular weight polyethylene fiber in the obtained fiber reinforced resin molded product was 56.0% by volume.

Table 7 shows the flexural strength and flexural modulus measured by the method described in Example 1.

Similarly, Table 8 shows the tensile yield strength and tensile elastic modulus measured by the method described in Example 1.

Comparative Example 2. The varnish having the composition used in Example 1 was put in a metal frame and heated to 160 ° C.
Press molding was performed for 6 minutes to obtain a 1.5 mm thick epoxy resin plate sample. The obtained sample was measured for flexural strength, flexural modulus, tensile yield strength and tensile modulus by the method described in Example 1. The results are shown in Table 9 and Table 10.

[Brief description of drawings]

FIG. 1 shows the endothermic curve of the silane-crosslinked stretched ultrahigh molecular weight polyethylene fiber prepared by the method of Example 1 measured under the restraint conditions in the differential scanning calorimeter at the first temperature rise. FIG. 2 shows the endothermic curve at the first temperature rise of the ultrahigh molecular weight polyethylene powder used in Example 1 molded into a press sheet having a thickness of 100 μ at 200 ° C. FIG. 3 shows the endothermic curve of the ungrafted stretched ultra high molecular weight polyethylene fiber prepared in Comparative Example 1 at the first temperature rise. In FIG. 4, the paraffin wax of the undrawn yarn silane-grafted in Example 1 was extracted with hexane at room temperature, impregnated with dibutyltin dilaurate, and then crosslinked by the method of Example 1 for the first ascent. The endothermic curve at warm temperature is shown. Further, FIG. 5 shows an endothermic curve of the silane crosslinked stretched ultra high molecular weight polyethylene fiber of FIG. 1 at the time of the second temperature increase (second run). 6 and 7 are schematic views of the molded fiber-reinforced resin molded product (although the number of laminated layers is different from that in the examples). FIG. 8 is a diagram showing the creep property of the stretch-oriented polyethylene fibers prepared in Example 1 and Comparative Example 1, which was 70 ° C. under a load of 30% of the breaking load measured at room temperature.
The results are measured under the atmosphere. FIG. 9 shows the relationship between the embedding length and the pull-out force in the adhesion test of the silane crosslinked stretched ultra high molecular weight polyethylene fiber prepared in Example 1 and the oriented ultra high molecular weight polyethylene fiber prepared in Comparative Example 1. It is a diagram showing.

Claims (5)

[Claims] 1. A thermosetting polymer matrix having a curing temperature of 220 ° C. or lower, and at least one layer of a molecular orientation and a reinforcing layer of silane-crosslinked ultrahigh molecular weight polyethylene fibers laminated or embedded in the matrix, A fiber-reinforced rubber molding, wherein the reinforcing layer substantially has an oriented crystal structure of ultrahigh molecular weight polyethylene fibers. 2. The crystal fusion of the ultrahigh molecular weight polyethylene, which is the molecular orientation and the silane crosslinked ultrahigh molecular weight polyethylene fiber, is determined as a main melting peak at the second temperature rise when measured by a differential scanning calorimeter in a restrained state. It has at least two crystal melting peaks (Tp) at a temperature at least 10 ° C higher than the temperature (Tm), and the heat of fusion based on this crystal melting peak (Tp) is 40% or more and the temperature range Tm + 35. The total amount of heat of fusion based on the melting peak (Tp ₁ ) on the high temperature side at ℃ to Tm + 120 ℃ is 5% of the total heat of fusion
The fiber-reinforced resin molded product according to claim 1, which has the characteristics described above. 3. The fiber-reinforced resin molded article according to claim 1, wherein the thermosetting polymer is an epoxy polymer. 4. The reinforcing layer is laminated or embedded over the entire surface of the molded product, and has a molecular orientation and a silane-crosslinked ultrahigh molecular weight polyethylene filament oriented in at least one axial direction of the molded product, or a nonwoven fabric composed of this filament. Claim 1 comprising a woven or knitted fabric
The molded article according to item. 5. A molecular orientation and filament of silane crosslinked ultra high molecular weight polyethylene, or a non-woven fabric, woven fabric or knitted fabric made of this filament is arranged in the plane direction and its end is restrained, and the curing temperature is 220 ° C. A method for producing a fiber-reinforced resin molded article, which comprises incorporating the following thermosetting polymer monomers and curing the monomer.