JPH08300537A - Fiber reinforced thermoplastic resin foam - Google Patents

Abstract

(57) [Abstract] [Purpose] To provide a fiber-reinforced thermoplastic resin foam excellent not only in tensile strength but also in compression strength. [Structure] A core layer 1 made of a thermoplastic resin foam having a closed cell ratio of 60% or more, and a fiber-reinforced thermoplastic resin fused to the surface of the core layer 1 so as to cover the outer peripheral surface of the core layer 1. With the structure including the skin layer made of resin, the compression load is borne by the cell wall of the foam of the core material layer 1, and the compression strength as a whole is improved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fiber reinforced thermal insulation comprising a core layer composed of a thermoplastic resin foam and a skin layer composed of a fiber reinforced thermoplastic resin layer fused to the outer peripheral surface thereof. It relates to a plastic resin foam.

[0002]

2. Description of the Related Art Thermoplastic resin foams have been used for various purposes since they are lightweight and have excellent shock absorption and heat insulating properties, but they have the drawback of weak mechanical strength. Was there. In order to solve such a drawback, there is known a fiber-reinforced resin foam in which the surface of a synthetic resin foam core material is fused and integrated with a fiber-reinforced resin skin layer.

For example, Japanese Patent Publication No. 53-4102 discloses that
Disclosed is synthetic wood in which a foamed thermoplastic resin inner filling layer is surrounded and integrated with a fiber-reinforced thermoplastic resin outer shell layer. By the way, in the technique disclosed in the above publication, for example, a plurality of vertical portions made of the same material as the outer shell layer (the first shell described in the above publication are provided so that the inner filling layer fills the plurality of cavities formed by the outer shell layer. By forming 1b) in Fig. 1, the strength as synthetic wood is exhibited.

[0004]

By the way, generally, the strength of a resin foam increases as the proportion of closed cells in all cells increases. In the method for producing synthetic wood described in the above publication, first, an inner filling layer is extruded from a foamed resin, and then a reinforcing outer shell layer is extruded from a non-foaming synthetic resin to surround the inner filling layer with a reinforcing outer shell layer. Therefore, according to the study by the present inventors, the open cell ratio of the inner filling layer is relatively high, and the vertical portion made of the same material as that of the outer shell layer is not provided inside (that is, the cavity is 1 In the case of the (individual) structure or the structure in which the number of vertical portions is small, the tensile strength is improved, but the compressive strength is as low as that of the thermoplastic resin foam alone. If the compressive strength of the fiber-reinforced thermoplastic resin foam is weak, it cannot be used in applications where a high compression load is applied, and when the bending load is applied, the strength of the compression side is the main factor for the entire foam. In the case of a thick foam having a fixed strength, the bending strength also becomes weak.

It is an object of the present invention to provide a fiber reinforced having not only a tensile strength but also a high compressive strength and bending strength even when the inner foam layer does not have a reinforcing layer such as the above-mentioned vertical portion of the above-mentioned prior art. It is to provide a thermoplastic resin foam.

[0006]

In order to achieve the above object, a fiber-reinforced thermoplastic resin foam of the present invention comprises a core material layer made of a thermoplastic resin foam having a closed cell ratio of 60% or more,
It is characterized by including a skin layer made of a fiber reinforced thermoplastic resin fused to the surface of the core material layer so as to cover the outer peripheral surface of the core material layer.

The thermoplastic resin used in the fiber-reinforced thermoplastic resin layer as a skin layer in the fiber-reinforced thermoplastic resin foam of the present invention includes polyethylene, polypropylene, polyvinyl chloride, polystyrene, polyamide and polyethylene terephthalate. , Polybutylene terephthalate, polycarbonate, polyvinylidene fluoride,
Examples thereof include polyphenylene sulfide, polyphenylene oxide, polyether sulfone, polyether ether ketone and polymethyl methacrylate.

Further, a copolymer containing the above-mentioned thermoplastic resin as a main component, a graft resin or a blend resin,
For example, chlorinated polyvinyl chloride, ethylene-vinyl chloride copolymer, vinyl acetate-ethylene copolymer, vinyl acetate-
Vinyl chloride copolymer, urethane-vinyl chloride copolymer,
Acrylonitrile-butadiene-styrene copolymer, acrylonitrile-styrene copolymer, silane-modified polyethylene, acrylic acid-modified polypropylene, maleic acid-modified polyethylene and the like can also be used. Further, a thermoplastic elastomer or a crosslinked thermoplastic resin can also be used.

Of these, considering the molding temperature,
Can be molded at a relatively low temperature of 120 to 250 ° C,
Polyethylene, polypropylene, polyvinyl chloride, polystyrene, chlorinated polyvinyl chloride, ethylene-vinyl chloride copolymer, vinyl acetate-ethylene copolymer, vinyl acetate-vinyl chloride copolymer, urethane-vinyl chloride copolymer, acrylonitrile -Butadiene-styrene copolymer and acrylonitrile-styrene copolymer can be preferably used.

Further, the above-mentioned thermoplastic resins may be used alone or in combination of two or more kinds, and further, within a range not impairing the physical properties, dibutyltin malate polymer, dibutyltin bis (monobutyltin) Alkyl malate) and other organic tin malates, dibutyltin malate, monobutyltin fatty acid salts and other organic tin laurate, dioctyltin sulfide, dibutyltin 3 mercaptopropionate and other organic tin mercapto-based heat stabilizers, fatty acids Ester wax, low molecular weight polyethylene wax, stearic acid, propylene glycol stearate, lubricants such as stearyl alcohol, processing aids such as acrylic resins and olefinic resins, plasticizers, antioxidants, ultraviolet absorbers, modifiers, Additives such as colorants, and talc, mica, calcium carbonate, wood flour, Fillers such as MC pulverized powder may be blended.

The fibers used in the fiber-reinforced thermoplastic resin layer of the skin layer in the present invention are optional as long as they are not melt-softened or carbonized by the heat applied in the manufacturing process of the fiber-reinforced thermoplastic resin foam. Can be used. Specifically, organic fibers such as glass fiber, carbon fiber, silicon / titanium / carbon fiber, boron fiber, fine metal fiber, aramid fiber, polyester fiber, polyamide fiber, silk, cotton, hemp, etc. Examples of the natural fibers include, but glass fiber and carbon fiber are preferable in consideration of strength and cost. The diameter of the filament is preferably 1 to 100 μm, particularly preferably 3 to 23 μm. The filament diameter is 1μ
When it is smaller than m, the reinforcing effect by the fiber becomes small, and when it is larger than 100 μm, the contact area between the thermoplastic resin and the fiber becomes smaller than that of a small diameter fiber of the same kind and the same weight. The effect becomes smaller.

The fiber in the fiber reinforced thermoplastic resin layer in the present invention is contained in the range of 5 to 80% by weight,
A range of 0% by weight is particularly preferred. When the content is less than 5% by weight, the reinforcing effect is small, and when the content is more than 80% by weight, the resin binding between the fibers is small and the reinforcing effect is also small.

The fibers in the fiber-reinforced thermoplastic resin layer have a length of 3 mm or more, preferably 1
It is 0 mm or more, and more preferably continuous fibers. The longer the reinforcing fibers, the stronger the strength (bending, tensile strength) of the fiber-reinforced thermoplastic resin foam as a whole, and if the fiber length is shorter than 3 mm, the reinforcing effect is small. Further, when it is desired to increase the mechanical strength (bending, tensile strength) in one direction, it is preferable that the reinforcing fibers are oriented in one direction, and in addition, the continuous fibers are oriented in one direction. Is most preferred.

The thickness of the fiber reinforced thermoplastic resin layer is 0.1
-10 mm is preferable, and 0.3-2 mm is more preferable. When the thickness is less than 0.1 mm, the effect of improving strength by the fiber reinforced thermoplastic resin layer is small, and when it is more than 10 mm, the whole weight becomes heavy, which is not preferable.

The skin layer in the fiber-reinforced thermoplastic resin foam of the present invention may be a single layer or a multi-layer in which a plurality of fiber-reinforced thermoplastic resin layers are laminated. Now, as the thermoplastic resin used in the thermoplastic resin foam that becomes the core layer of the fiber-reinforced thermoplastic resin foam of the present invention, the same thermoplastic resin as that used in the fiber-reinforced thermoplastic resin layer that is the skin layer is used. Although a thermoplastic resin used as the fiber-reinforced thermoplastic resin can be used, it is preferable to use a thermoplastic resin that can be heat-sealed. Specifically, it is preferable to use thermoplastic resins of the same type (thermoplastic resins polymerized from the same monomer).

When different kinds of thermoplastic resins are used for the core material layer and the skin layer, for example, a combination of polyethylene and polypropylene, polyethylene and vinyl acetate-ethylene copolymer, polyethylene and chlorinated polyethylene,
Polystyrene and acrylonitrile-butadiene-styrene copolymer, polystyrene and acrylonitrile-styrene copolymer, polyvinyl chloride and chlorinated polyvinyl chloride,
Polyvinyl chloride and ethylene-vinyl chloride copolymer, polyvinyl chloride and vinyl acetate-vinyl chloride copolymer, polyvinyl chloride and urethane-vinyl chloride copolymer, polyvinyl chloride and polymethylmethacrylate, polyvinyl chloride and acrylonitrile -Butadiene-styrene copolymer, polybutylene terephthalate and polyethylene terephthalate, acrylonitrile-butadiene-styrene copolymer and acrylonitrile-styrene copolymer and the like.

It is also possible to use a combination of a thermoplastic resin and a modified thermoplastic resin of the same type. Examples of this include polyethylene and silane-modified polyethylene,
Examples thereof include polyethylene and acrylic acid-modified polypropylene, polyethylene and maleic acid-modified polyethylene, and the like.

The expansion ratio of the thermoplastic resin foam of the core layer is
It should be appropriately selected depending on the strength and specific gravity required for the product, the type of thermoplastic resin used, etc., but 1.2 to 3
A range of 0 times is preferable. If the expansion ratio is less than 1.2 times, the effect of weight reduction due to foaming is small and 30
If it exceeds 2 times, the mechanical strength such as compressive strength and bending strength becomes particularly weak.

Here, the thermoplastic resin used for the core layer and the thermoplastic resin used for the skin layer are most preferable among the above-mentioned resins, and are particularly excellent in flame retardancy. Polyvinyl chloride, suitable for use as a building material. Another preferable resin is an olefin resin such as polyethylene or polypropylene, which has excellent recyclability and is suitable for use as an automobile member, a home electric appliance or the like.

However, the foaming temperature of azodicarbonamide, which is a preferred foaming agent for olefin resins, is 199-2.
In the preferred method for producing a fiber-reinforced thermoplastic resin foam of the present invention (described later), the melt viscosity of polyethylene is too low, the number of foam breakage increases, and the rigidity and heat resistance of the resin are increased. From the viewpoint, polypropylene is more preferable among the olefin resins.

When the polyvinyl chloride or the olefin resin is used as the fiber reinforced thermoplastic resin layer, the preferable conditions are summarized as follows.
3 μm continuous glass fibers are oriented in the longitudinal direction, the content thereof is 10 to 50% by weight, and the thickness of this reinforcing layer is in the range of 0.3 to 2 mm. In the range of this thickness, the larger the thickness, the more the preferred method for producing the fiber-reinforced thermoplastic resin foam of the present invention (described later) is to prevent outgassing from the core layer and increase the closed cell ratio of the core layer. be able to.

When polyvinyl chloride is used as the foam layer, the expansion ratio is preferably in the range of 1.5 to 10 times, and this range is a range in which light weight and high strength can be obtained. When the expansion ratio exceeds 10 times, it becomes difficult to obtain a high closed cell rate.

On the other hand, when an olefin resin is used for the foam layer, the expansion ratio is preferably in the range of 1.5 to 20 times. With this olefin resin, it is relatively easy to increase the closed cell ratio within the range of the expansion ratio.

In the fiber reinforced thermoplastic resin foam of the present invention, the closed cell ratio of the thermoplastic resin foam of the core layer is 60%.
Above, the greater the closed cell rate, the greater the compressive strength,
It is more preferably 70% or more, still more preferably 80% or more. If the closed cell ratio is less than 60%, excellent compressive strength cannot be obtained. Further, from the viewpoint of strength, the higher the closed cell rate, the more preferable, but due to the restrictions on the manufacturing method, the upper limit of the closed cell rate is generally about 90% in the case of polyvinyl chloride resin and 95 in the case of polyolefin resin. It is said to be about%.

Here, the closed cell ratio in the present invention can be measured by a commercially available measuring device which is generally used, for example, an air comparison type hydrometer. That is, it can be calculated from the ratio of the volume of the air-containing portion (volume of open cells) to the volume of the portion without air (closed-cell volume) when air is pressed into the foam.

Next, an example of the method for producing the fiber-reinforced thermoplastic resin foam of the present invention will be described. A fiber-reinforced thermoplastic resin sheet is formed into a hollow body, and the foamable thermoplastic resin composition is formed inside the hollow body. Can be extruded while foaming, and the shape of the hollow body can be shaped by aligning the outer surface of the hollow body with a regulation member such as a mold by the foaming pressure. The hollow body referred to here is a state in which the end portions of the sheet are abutted against each other or overlapped with each other, in addition to a state in which a void is formed inside the sheet, between the side edge portions of the sheet. Including those with a slight gap. The fiber-reinforced thermoplastic resin sheet may be shaped into a hollow body by using only one sheet, or by using a plurality of sheets and making them parallel to the longitudinal direction, Butt or overlap the side edges,
Alternatively, they may be shaped into one hollow body as a whole by butting them with a slight gap therebetween.

As a method of shaping the fiber reinforced thermoplastic resin sheet into a hollow body, a method of gradually bending it with a shoe or roll made of synthetic resin can be mentioned. Further, as another method of shaping the sheet into a hollow body, it is also possible to adopt a method of using a mold in which a sheet passage is formed so that the sheet is gradually bent and shaped into a hollow body. it can. At the time of shaping into this hollow body, in order to prevent the sheet from cracking or tearing, it is desirable that the thermoplastic resin is shaped in a softened state by heating with a far infrared heater or a hot air blower.

Here, the softened state means JIS K720.
The state in which the thermoplastic resin is heated to the Vicat softening temperature or higher, measured according to 6, is indicated. Generally, it refers to a state in which the thermoplastic resin begins to deform and is heated to a temperature at which the mechanical properties deteriorate.

As a method of supplying the foamable thermoplastic resin composition while foaming it into the shaped hollow body, a nozzle of an extruder is installed on the inner surface side of the hollow body to foam the thermoplastic resin. A method of extruding while pointing is included. In this case, in the extruder, the expandable thermoplastic resin composition containing a decomposing type foaming agent or a volatile type foaming agent is kneaded at a gas generation temperature or higher, and the generated gas is dispersed in the thermoplastic resin to form a foaming agent. The thermoplastic resin composition is supplied to the inside of the hollow body from a nozzle whose temperature is adjusted to the melting temperature or higher. Alternatively,
While kneading the thermoplastic resin at the melting temperature or higher, gas such as carbon dioxide or nitrogen is pressed in, dispersed in the thermoplastic resin, and supplied into the hollow body from a nozzle whose temperature is adjusted to the melting temperature of the thermoplastic resin or higher. .

As another method for producing the fiber-reinforced thermoplastic resin foam of the present invention, the expandable thermoplastic resin beads, or the expandable thermoplastic resin beads may be provided inside the fiber-reinforced thermoplastic resin sheet formed into a hollow body by the above-mentioned method or the like. After the sheet is supplied, the sheet is heated to be foamed, and the foaming pressure causes the outer surface of the hollow body to be shaped along a regulating member such as a mold, thereby shaping the hollow body. In this case, as a method of supplying the heat-foamable thermoplastic resin to the inside of the hollow body, the nozzle of the extruder is installed in the hollow body, the foamable thermoplastic resin at the melting temperature of the resin or higher, and Examples thereof include a method of extruding at a temperature equal to or lower than the decomposition temperature of the foaming agent, a method of continuously supplying a bead-shaped or sheet-shaped expandable thermoplastic resin composition into the hollow body.

As a method of foaming the expandable thermoplastic resin composition in the hollow body, a method of inserting the whole hollow body into a mold heated to a high temperature, a method of blowing hot air into the inside of the hollow body, etc. Can be adopted. When blowing hot air into the hollow body, an air pipe is provided through the resin supply port and the inside of the outer shape regulating member of the hollow body, and a manufacturing apparatus having a structure capable of uniformly supplying hot air to the hollow body is used. There is a need.

The fiber-reinforced thermoplastic resin sheet used in each of the above production methods can be produced, for example, by the following methods. One of them is to disintegrate a continuous reinforced glass fiber bundle into filaments, align them in one direction, and then stack films made of thermoplastic resin and pass them between heating pinch rolls to strengthen the molten thermoplastic resin. It is a method of obtaining a fiber-reinforced thermoplastic resin sheet by infiltrating between filaments of a fiber.

The other one is to draw a continuous reinforcing fiber bundle aligned in one direction into a tank in which a powdery thermoplastic resin is flowing, and defibrate the reinforcing fiber bundle into a filament form,
This is a method in which a powdery thermoplastic resin is adhered and then passed between heating pinch rolls to melt the thermoplastic resin and infiltrate between filaments to form a sheet.

Further, when it is desired to obtain a fiber-reinforced thermoplastic resin sheet in which the fibers are oriented in a random state, the reinforcing fiber bundle to which the powdered thermoplastic resin obtained as described above is attached is used. , Shredded with a rotary cutter, dropped and accumulated on an endless belt, pressed against another endless belt from above, and passed through the heating furnace while being sandwiched between these upper and lower endless belts while being pressed, A method may be adopted in which a softened and melted thermoplastic resin is allowed to enter between the filaments of the reinforced fibers that have been shredded and then passed through a cooling roll to form a sheet.

In the above-mentioned manufacturing method, the expandable thermoplastic resin composition comprises the above-mentioned thermoplastic resin, a foaming agent, a stabilizer, a lubricant, and a stabilizer which are similar to those added to the fiber-reinforced thermoplastic resin layer. It can be obtained by mixing a processing aid and a filler.

As the foaming agent, there can be used a decomposing type foaming agent which chemically decomposes to generate gas and a physical foaming agent which utilizes gasification of a volatile liquid. Further, as described above, while kneading the thermoplastic resin at a melting temperature or higher, a gas such as carbon dioxide or nitrogen may be injected under pressure to be dispersed in the thermoplastic resin, and the pressure may be released for foaming. Further, so-called foam beads obtained by dissolving and dispersing a volatile liquid, carbon dioxide, nitrogen, etc. in a thermoplastic resin can also be used.

As the decomposition type foaming agent, azodicarbonamide, azobisisobutyronitrile, N, N'-dinitrosopentamethylenetetramine, pp'-oxybisbenzenesulfonyl hydrazide, barium azodicarboxylate, trihydrazinotriazine. , P-trienesulfonyl hydrazide, sodium hydrogen carbonate, ammonium carbonate and the like. As the physical type blowing agent, propane, butane, pentane, hexane, aliphatic hydrocarbons such as heptane, methyl chloride, chlorinated aliphatic hydrocarbons such as methylene dichloride, 1,1-dichloro-1-fluoroethane,
2,2-dichloro-1,1,1-trifluoroethane,
Freon gas such as 1,1,1,2-tetrafluoroethane may be used.

The amount of the foaming agent to be blended must be appropriately adjusted because the amount of gas generated varies depending on the type of the foaming agent, but with respect to 100 parts by weight of the thermoplastic resin,
It is preferably blended in the range of 0.5 to 15 parts by weight. If the blending amount of the foaming agent is too small, a foamed molded article cannot be obtained, and if the blending amount of the foaming agent is too large, the cell walls are broken and the closed cell ratio becomes low. For example, when a thermoplastic resin foam having a foaming ratio of 10 times is produced using azodicarbonamide, the amount is 5 per 100 parts by weight of the thermoplastic resin.
It is suitable to mix up to 6 parts by weight.

The closed cell ratio of the foam constituting the core material layer is 6
The most effective method for adjusting the content to 0% or more is to add an appropriate amount of a foaming agent as described below. Other conditions may include adjustment of the resin melt viscosity during the foaming process.

When a polyvinyl chloride resin is used as the foaming resin, it is preferable to use azodicarbonamide or sodium bicarbonate as the foaming agent, and when it is desired to make the expansion ratio 1.5 to 10 times, polyvinyl chloride is used. It is preferable to mix 0.5 to 5 parts by weight of any one of these foaming agents with 100 parts by weight of the base resin. Although it depends on the application, a more preferable foaming ratio is 2 to 7 in terms of having both lightness and strength.

When an olefin resin is used as the resin of the foam, it is preferable to use azodicarbonamide as a foaming agent. When it is desired to increase the expansion ratio to 1.5 to 20, the amount of azodicarbonamide is 100 parts by weight of the olefin resin. It is preferable to mix 0.5 to 10 parts by weight of azodicarbonamide.

The melt viscosity can be adjusted by adjusting the molecular weight, the molecular weight distribution,
Alternatively, the degree of cross-linking and the like can be adjusted depending on the type of the thermoplastic resin used, and can also be adjusted by the temperature of the thermoplastic resin in the foaming process. In order to obtain a closed cell ratio of 60% or more, the shear viscosity in the foaming process should be 1500
It is preferable to set it to about 30,000 poise.

When a polyvinyl chloride resin is used as the foaming layer, the (melting) shear viscosity at the time of foaming varies greatly depending on the type and amount of the lubricant to be mixed, but the average degree of polymerization is 70.
A high closed cell ratio can be obtained by blending 0 to 1000 polyvinyl chloride resin with 5 to 15 parts by weight of an acrylic processing aid in addition to a heat stabilizer and a lubricant. If the degree of polymerization is less than 700, the viscosity is low and the foam tends to break. The degree of polymerization is 100
If it exceeds 0, the viscosity is too high to cause foaming.

When a plasticizer which is widely used for promoting plasticization of vinyl chloride resin is added, the closed cell ratio of the foam layer increases, but the compressive strength remarkably decreases. Is good. If a large amount of a filler such as calcium carbonate, talc, or fiber is used, outgassing at the time of forming the foam layer increases, and the closed cell ratio decreases. Therefore, it is preferable not to add 5 parts by weight or more.

Further, when a vinyl chloride resin is used for the foam layer, it is preferable that the resin is foamed while being extruded into the hollow body in the above-mentioned production method, and the resin temperature at the time of extrusion is in the range of 150 to 180 ° C. It is preferable. When the resin temperature is too high, the viscosity of the resin becomes low and the bubbles are easily broken.

On the other hand, when an olefin resin is used for the foam layer, the shear viscosity in the foaming process is 1500-300.
00 poises are preferable, but 3000-2 are more preferable.
It is in the range of 5000 poise. As a means for adjusting the viscosity within this range, there is a method using crosslinking. Crosslinking of the olefin resin includes a method by electron beam irradiation and a method by chemical crosslinking using a crosslinking agent.

The cross-linking by electron beam irradiation is carried out, for example, by forming a thin sheet and then irradiating it with an electron beam. Also, the chemical cross-linking is dicumyl peroxide or 2,
It is carried out by kneading an organic peroxide such as 5-dimethyl-2,5-di (t-butylperoxy) hexane with a resin to decompose the organic peroxide. There is also a method in which an organic peroxide and a silane coupling agent such as vinyltrimethoxysilane and vinyltriethoxysilane are kneaded with an olefin resin by heating, silane-grafted, and then crosslinked by water treatment. Here, water treatment refers to treatment such as humidification or immersion in steam or hot water.

The preferred cross-linking weight percentage is 10-75%.
Is. If it is 10% or less, there is no crosslinking effect, and if it is 75% or more, the viscosity at the time of foaming is too high to cause foaming. The degree of cross-linking of the cross-linked thermoplastic resin is to dissolve the part of the non-cross-linked thermoplastic resin, and use a solvent that does not dissolve the cross-linked thermoplastic resin to remove the non-cross-linked thermoplastic resin and remove the residual content. It can be known by measuring.
In the case of offine resin, 24
It is soaked in time and expressed as a weight ratio of the remaining one.

When the olefin resin is used as the foam layer, it is preferable that the hollow body in the above-mentioned manufacturing method be foamed while being extruded, or that a sheet or pellet having a heat-foaming property is used. The temperature of the resin during extrusion is preferably 180 to 230 ° C. If the resin temperature is lower than this range, it will not foam, and if it is too high, the viscosity of the resin will be low and the foam will be easily broken. The heat-foamable sheet or pellet is obtained by adding a foaming agent to an olefin resin, and further, when cross-linking, by compounding the compounding agent such as the above-mentioned organic peroxide, the sheet or the pellet at a temperature at which the foaming agent does not foam. It is obtained by processing into a pellet shape.

The fiber-reinforced polyvinyl chloride resin layer or the fiber-reinforced olefin resin layer has a diameter of 3 to 2
3 μm continuous glass fibers are oriented in the longitudinal direction, the content is 10 to 50% by weight, and the thickness is 0.3 to 20 mm. It is easy to prevent gas escape from the core layer, and the closed cell ratio Of 60% or more is preferable in that a core material layer can be obtained.

[0051]

In the fiber-reinforced thermoplastic resin foam of the present invention, the thermoplastic resin foam, which is the core material layer, has a closed cell ratio of 60% or more, and the cell wall of the core material layer has a load against the compression load. Therefore, it exhibits excellent compressive strength as a whole.

Here, in the case where only the foam layer is molded by itself, especially when aiming for a high expansion ratio, it is difficult to obtain a high closed cell rate because a large amount of gas escapes from the outside. Since the fiber-reinforced thermoplastic resin foam has a structure in which the fiber-reinforced thermoplastic resin layer is arranged on the outer periphery of the foam layer, the fiber-reinforced thermoplastic resin sheet is made into a hollow body, and the foamable thermoplastic resin composition is contained therein. When the manufacturing method of supplying / foaming a material is adopted, it is possible to prevent gas escape from the outermost portion of the foamed layer and increase the closed cell rate.

[0053]

EXAMPLES Examples of the present invention will be described below together with comparative examples. <Example 1> Production of fiber-reinforced thermoplastic resin sheet (skin layer) Glass fiber bundle (glass roving, 4400 g / km,
(Fiber diameter: 23 μm) Air is blown onto four filaments to break them into filaments and align them in a plane, and polypropylene film (melt flow rate 30, thickness 0.35 mm)
Are laminated and heated with a pinch roll heated to 220 ° C for 10
The polypropylene was melted by heating under pressure of kg / cm ² and impregnated between the glass fibers. Then, while cooling with a cooling pinch roll, trimmed to a width of 100 mm, thickness 0.4 mm, glass fiber content 32% by weight
A glass fiber reinforced polypropylene sheet of
This is referred to as fiber reinforced sheet A). Blending of expandable thermoplastic resin (core material layer) As the expandable thermoplastic resin, polypropylene was blended as shown in [Table 1] below, kneaded with a biaxial kneader, pelletized, and then steamed at 120 ° C. It was used after being humidified for 1 hour. The weight ratio of the crosslinked portion of the obtained pellets is 18%
Met.

[0054]

[Table 1]

Manufacturing Device and Mold for Fiber Reinforced Thermoplastic Resin Foam As shown in the cross-sectional view of FIG. 1, the manufacturing device used in this embodiment 1 is a fiber reinforced sheet feeding machine 11, a pellet feeder 12, and a forming machine. Member 13, heating shaping mold 14,
The cooling mold 15 and the product take-up machine 16 are the main components.

The forming member 13 is the fiber-reinforced sheet A fed from the fiber-reinforced sheet feeding machine 11.
Is a member composed of, for example, a shoe or a roll, which can be continuously shaped into a hollow cylindrical body through a semicylindrical shape.

The pellet feeder 12 has a structure capable of supplying pellets to the inside of the fiber reinforced sheet A formed in a semi-cylindrical shape by the forming member 13. The fiber reinforced sheet A is provided with the pellets after the pellets have been supplied. It is shaped into a perfect cylinder and is guided to the heat shaping mold 14. The heating shaping mold 14 and the cooling mold 15 each have a cross section of 25 m.
It is a mold having a square cavity of m × 25 mm. Manufacturing Conditions for Fiber Reinforced Thermoplastic Resin Foams, etc. A heating shaping mold in which a hollow body made of a fiber reinforced sheet A having pellets having the composition shown in [Table 1] supplied therein is temperature-controlled at 250 ° C. 14, the pellets are foamed in the fiber reinforced sheet A, the fiber reinforced sheet A is pressed by the foaming pressure against the inner surface of the mold to be shaped, and further cooled by the cooling mold 15, and the cross-section is shown in FIG. As shown in the figure, a fiber-reinforced thermoplastic resin foam having a structure in which the outer peripheral surface of a core material layer 1 made of a thermoplastic resin foam is integrally covered with a skin layer 2 made of a fiber-reinforced thermoplastic resin. Got the body

Only the core layer of the obtained fiber-reinforced thermoplastic resin foam was taken out and the specific gravity was measured.
(Expansion ratio 5.5 times). The closed cell content was 84%. The result of the bending test was a bending strength of 0.45 kgf / mm ² . The test method is 3
A point bending test is performed, and the test conditions are 1200 between fulcrums.
mm, test speed 20 mm / min (Note that this test method and test conditions are described in Example 2 and Comparative Example 1 below).
The same applies to 2). <Example 2> Production of fiber-reinforced thermoplastic resin sheet (skin layer) Glass fiber bundle (glass roving, 4400 kg / k)
m, fiber diameter 23 μm) 4 pieces of polyvinyl chloride resin are blended and blended as shown in [Table 2] below, and the mixture is drawn into a fluidizing tank and the glass fiber bundle is drawn into a filament. Polyvinyl chloride resin was attached while being broken into units. The glass fibers to which the polyvinyl chloride resin has been attached are aligned in a plane, and heated while being pressurized at 10 kg / cm ² by a pinch roll heated to 220 ° C to melt the polyvinyl chloride resin Impregnated between the fibers. It is then cooled with a cooling pinch roll to a width of 100
Trimming was performed to obtain a fiber-reinforced polyvinyl chloride resin sheet having a thickness of 0.4 mm and a glass fiber content of 23% by weight (hereinafter, referred to as fiber-reinforced sheet B).

[0059]

[Table 2]

Mixing of expandable thermoplastic resin (core material layer) As the expandable thermoplastic resin, polyvinyl chloride compounded as shown in [Table 3] below was used. The compounding was performed using a super mixer until the resin temperature reached 100 ° C.

[0061]

[Table 3]

Manufacturing Device and Mold for Fiber Reinforced Thermoplastic Resin Foam The manufacturing device used in this Embodiment 2 is, as shown in the sectional view of FIG.
2, the extrusion die 23, the shaping die 24, the cooling die 25, and the product take-up machine 26 are the main constituent elements.

The extrusion die 23 includes an outer die 23a and an inner die 2.
3b, and a sheet passage is formed between the outer die 23a and the inner die 23b. This sheet passage has an inverted U-shaped cross section at the end face of the extrusion die 23 on the delivery machine 21 side.
The opening is in the shape of a letter, and the cross-section gradually changes to a perfect circle as it goes to the right in the figure. The fiber reinforced sheet B delivered from the delivery machine 21 is gradually shaped into a cylindrical hollow body whose both side edges are abutted against each other by passing through the sheet passage of the extrusion die 23. Go. The inner mold 23b includes a horizontal portion to be inserted into the hollow body and a vertical portion that bends downward at one end of the horizontal portion, and the extruder 2 is provided at the lower end of the vertical portion.
2 is connected to the horizontal part, and the horizontal part is inserted into the inside of the fiber-reinforced sheet B from the opening part having an inverted U-shaped section in the process of shaping, and the tip part is a part where the fiber-reinforced sheet B becomes a completely hollow body. Has reached. A resin flow path having a diameter of 5 mm, which communicates from the extruder 22 to the tip of the horizontal portion, is formed in the inner mold 23b, and the extruder 22 is provided in the hollow fiber-reinforced sheet B. The following expandable thermoplastic resin composition discharged from the above can be extruded.

The shaping mold 24 and the cooling mold 25 each have a cross section of 25 mm × 25 m, as in the first embodiment.
It is a mold with a square cavity of m. Manufacturing conditions of fiber-reinforced thermoplastic resin foam, etc. After inserting the fiber-reinforced sheet B into the sheet passage of the extrusion die 23 whose temperature is adjusted to 250 ° C. and shaping it into a hollow body in the extrusion die 23, Polyvinyl chloride having the composition shown in [Table 3] was extruded therein while foaming. It is introduced into the shaping mold 24 heated at 180 ° C. after extruding polyvinyl chloride, and the fiber reinforced sheet B is shaped by the foaming pressure.
The inner surface of the shaping die 24 is shaped into the same contour as the inner shape of the cross section of the shaping die 24, and is cooled by the cooling die 25, whereby the fiber reinforced having the same cross sectional shape as that shown in FIG. A thermoplastic resin foam was obtained.

The specific gravity of only the core layer of the obtained fiber-reinforced thermoplastic resin foam was 0.37 (foaming ratio 3.8 times), and its closed cell content was 75%. . The bending strength was 0.74 kgf / mm ² . Comparative Example 1 Production of Fiber Reinforced Thermoplastic Resin Sheet (Skin Layer) The same procedure as in Example 1 was performed. Blending of expandable thermoplastic resin (core material layer) The expandable thermoplastic resin is prepared by blending polypropylene as shown in [Table 4] below, kneading with a biaxial kneader, pelletizing, and then steaming at 120 ° C. It was used after being humidified for 1 hour.

[0066]

[Table 4]

Device for Manufacturing Fiber-Reinforced Thermoplastic Resin Foam and Mold The same as in Example 1. Manufacturing Conditions of Fiber Reinforced Thermoplastic Resin Foam As the same as Example 1, a fiber reinforced thermoplastic resin foam having exactly the same cross-sectional shape as that shown in FIG. 2 was obtained.

The specific gravity of only the core layer of the obtained fiber-reinforced thermoplastic resin foam was 0.17 (foaming ratio: 5.5 times), and its closed cell ratio was 51%. Bending strength is 0.
It was 38 kgf / mm ² . Comparative Example 2 Production of Fiber Reinforced Thermoplastic Resin Sheet (Skin Layer) The same procedure as in Example 2 was performed. Blending of expandable thermoplastic resin (core material layer) As the expandable thermoplastic resin, a mixture of polyvinyl chloride and [Table 5] was used. The compounding was performed using a super mixer until the resin temperature reached 100 ° C.

[0069]

[Table 5]

Device for Manufacturing Fiber-Reinforced Thermoplastic Resin Foam and Mold The same as in Example 2. Manufacturing Conditions of Fiber Reinforced Thermoplastic Resin Foam As in Example 2, a fiber reinforced thermoplastic resin foam having exactly the same cross-sectional shape as that shown in FIG. 2 was obtained.

The specific gravity of only the core layer of the obtained fiber reinforced thermoplastic resin foam was 0.37 (foaming ratio 3.8),
The closed cell rate was 55%. Bending strength is 0.63
It was kgf / mm ² .

An air-comparison hydrometer 1000 manufactured by Tokyo Science was used to measure the closed cell content of the core layer of the products obtained in each of the above Examples and Comparative Examples. A compression test was performed on the molded articles obtained in the above Examples and Comparative Examples. The results are shown in [Table 6] together with the measurement results of the closed cell ratio of the core layer described above. The test method of the compression test shall be in accordance with JIS K7220 (compression test method for hard foam plastics), and the test speed shall be 5 m.
m / min, and the shape of the test piece was 25 × 25 × 50 mm. In addition, in [Table 6], the compression strength has a value in the compression proportional limit.

[0073]

[Table 6]

From the above results, in the fiber-reinforced thermoplastic resin foams obtained in the respective examples of the present invention, the core material layer has a closed cell ratio of 60% or more, which is higher than those obtained in the comparative examples. It was confirmed that the compressive strength was significantly excellent and the bending strength was also excellent.

[0075]

As described above, according to the present invention,
Tensile strength mainly carried by the fiber-reinforced thermoplastic resin layer by setting the closed cell ratio of the core layer made of the thermoplastic resin foam whose outer periphery is covered with the skin layer made of the fiber-reinforced thermoplastic resin to be 60% or more. Not only does it show excellent compressive strength, but as a result, especially when a thick fiber-reinforced thermoplastic resin foam is used, the strength on the side where compressive stress acts, even with bending load. Of the fiber-reinforced thermoplastic resin foam is suitable for applications such as building materials.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing the configuration of an apparatus for producing a fiber-reinforced thermoplastic resin foam used in Example 1 of the present invention.

FIG. 2 is a schematic cross-sectional view showing the structure of a fiber-reinforced thermoplastic resin foam obtained by the apparatus of FIG.

FIG. 3 is a cross-sectional view showing the configuration of a fiber-reinforced thermoplastic resin foam manufacturing apparatus used in Example 2 of the present invention.

[Explanation of symbols]

 1 Core Material Layer 2 Skin Layer 12 Pellet Supply Machine 13 Forming Member 14 Heating Molding Mold 15 Cooling Mold 22 Extruder 23 Extrusion Molding 24 Shaping Molding 25 Cooling Molding

Claims (1)

[Claims] 1. A core material layer made of a thermoplastic resin foam having a closed cell ratio of 60% or more, and a fiber-reinforced thermoplastic resin fused to the surface of the core material layer so as to cover the outer peripheral surface of the core material layer. A fiber-reinforced thermoplastic resin foam comprising a skin layer.