JP2002192670A - Laminated sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a laminated sheet which shows superb thermoformability and also superiority in terms of lightweight properties, bending strength, compression strength, dimensional stability and recycling characteristics. SOLUTION: This laminated sheet A is characterized in that polyolefin resin sheets 2 and 2 in which a liquid crystal resin fiber 21 is dispersed are integrally laminated on both sides of a polyolefin resin expanded sheet 1 having spindle- shaped cells 11 with an aspect ratio (Dz/Dxy) of 1.2 or more, orientated in such a state that the position of the cells is changed from the lengthwise direction to the thickness direction. Consequently, the laminated sheet A shows excellent thermoformability and also outstanding bending strength, compression strength and dimensional stability. For these reasons, the laminated sheet A is suitably used for interior members for vehicles, heat insulating materials, shock absorbing materials and the like.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laminated sheet excellent in lightweight, bending strength, compressive strength, thermoformability and dimensional stability.

[0002]

2. Description of the Related Art Conventionally, foams made of a thermoplastic resin have been used for various heat insulating materials, cushioning materials, flotation materials and the like because of their excellent lightness, heat insulating properties and flexibility. Among them, polyolefin resin foams are particularly widely used for interior parts such as vehicle doors, ceilings, and instrument panels by secondary thermoforming due to their excellent heat resistance and dimensional stability. Have been. And
Japanese Patent Application Laid-Open No. 6-134913 discloses a laminated molded product obtained by joining and integrating a laminated body obtained by laminating fiber-reinforced thermoplastic resin plates in layers to a surface of a foamed resin body having a desired outer shape. Proposed.

[0003] However, since the fiber-reinforced thermoplastic resin plate of the laminated molded product is reinforced with glass fiber, when the laminated molded product is deep-drawn, it is contained in the fiber-reinforced thermoplastic resin plate. There is a problem that the glass fiber is broken because it cannot follow the deformation of the laminated molded product, and the mechanical strength of the molded product obtained from the laminated molded product is reduced. Cannot be applied to deep drawing, and a molded article having a complicated shape cannot be obtained.

[0004]

SUMMARY OF THE INVENTION The present invention provides a laminated sheet which is excellent in thermoformability and excellent in light weight, bending strength, compressive strength, dimensional stability and recyclability.

[0005]

According to a first aspect of the present invention, there is provided a laminated sheet according to the first aspect, wherein spindle-shaped bubbles having an aspect ratio (Dz / Dxy) of 1.2 or more have their length direction oriented in the thickness direction. A polyolefin resin sheet in which liquid crystal resin fibers are dispersed is laminated and integrated on both surfaces of the oriented polyolefin resin foam sheet.

According to a second aspect of the present invention, there is provided the laminated sheet according to the first aspect, wherein 0.5 to 30% by weight of a liquid crystal resin fiber is foamed in the polyolefin resin foam sheet in the longitudinal direction. It is characterized by being dispersed in a state oriented in the thickness direction of the sheet.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An example of the laminated sheet of the present invention will be described with reference to the drawings. The laminated sheet has a liquid crystal resin on both sides of a polyolefin resin foam sheet in which spindle-shaped bubbles having an aspect ratio (Dz / Dxy) of 1.2 or more are oriented in a state where the length direction thereof is oriented in the thickness direction. A polyolefin resin sheet in which fibers are dispersed is laminated and integrated.

The polyolefin resin used in the polyolefin resin foam sheet is not particularly limited as long as it has been conventionally widely used for foams.
Polyethylene such as low-density polyethylene, linear low-density polyethylene, medium-density polyethylene, and high-density polyethylene, isotactic polypropylene, polypropylene such as syndiotactic polypropylene, polybutene,
Examples include an ethylene-α-olefin copolymer, and polyethylene or polypropylene is preferable, and a mixture of polyethylene and polypropylene is more preferable. In addition, propylene, 1-butene,
Examples thereof include 1-pentene, 1-hexene, 4-methyl-1-pentene, 1-heptene, and 1-octene. Examples of the copolymer containing an ethylene component include a block copolymer and a random copolymer. Alternatively, any of a random block copolymer may be used.

Further, since the above-mentioned polyolefin-based resin needs to have a certain degree of elongational stress at the time of foaming, a crosslinked structure may be provided by the following method, for example. That is, as a first crosslinking method, in order to obtain a polyolefin resin foam sheet excellent in light weight and recyclability by imparting fluidity and elongation stress within a desired range during foaming to the polyolefin resin, After adding a polyolefin-based resin and a polyfunctional monomer having two or more functional groups capable of undergoing a radical reaction to an organic peroxide as necessary, supply it to a general-purpose melt-kneading apparatus such as an extruder or a kneader, While adjusting the melt viscosity of the polyolefin-based resin so that the polyolefin-based resin can be smoothly melt-kneaded, a polyfunctional monomer is reacted with the polyolefin-based resin in the melt-kneading apparatus to obtain a modified polyolefin-based resin. That is, a polyfunctional monomer is allowed to react with the polyolefin-based resin, and finally, the polyolefin-based resin is to be provided. After introducing a part of the bridge structure into the polyolefin-based resin and forming it into a desired shape such as a sheet, the modified polyolefin-based resin is further crosslinked to the polyolefin-based resin by heating to a reaction temperature of the polyfunctional monomer or higher. A method of giving a structure and giving an elongation stress suitable for foaming can be given. When a divinyl compound or an allyl-based polyfunctional compound is used as the polyfunctional monomer, it is preferable to add an organic peroxide.

Examples of the polyfunctional monomer include dioxime compounds, bismaleimide compounds, divinyl compounds, allyl polyfunctional compounds, (meth) acrylic polyfunctional compounds, and quinone compounds.

The dioxime compound includes the oxime group shown in Chemical formula 1 or a substituted oxime group shown in Chemical formula 2 in which a hydrogen atom in this oxime group is substituted with another atomic group R (mainly a hydrocarbon group). Means a compound having either one or two or both one by one,
Specific examples include p-quinone dioxime represented by Chemical formula 3, p, p'-dibenzoylquinone dioxime represented by Chemical formula 4, and the like. The dioxime compounds may be used alone or in combination.

[0012]

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[0013]

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[0014]

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[0015]

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The bismaleimide compound means a compound having two or more maleic imide (maleimide) structures shown in Chemical Formula 5, for example, N, N'-p-phenylene shown in Chemical Formula 6. Bismaleimide, N, N'-m-phenylenebismaleimide shown in Chemical formula 7, Chemical formula 8
And a polymaleimide having two or more maleimide structures in the molecule as shown in Chemical formula 9 is also included in the bismaleimide compound.

[0017]

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[0018]

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[0019]

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[0020]

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[0021]

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Examples of the divinyl compound include o-divinylbenzene, m-divinylbenzene and
p-divinylbenzene and the like.

[0023]

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The allyl-based polyfunctional compound means a compound having two or more allyl groups (CH ₂ ＣＨCHCH ₂ —) in the molecule. Examples include triallyl cyanurate as shown, triallyl isocyanurate as shown in Chemical formula 13, and diallyl chlorendate as shown in Chemical formula 14.

[0025]

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[0026]

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[0027]

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[0028]

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The above (meth) acrylic polyfunctional compounds include alkanediol di (meth) acrylate, ethylene glycol di (meth) acrylate, propylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, and polypropylene glycol di (meth) acrylate. (Meth) acrylate, neopentyl glycol di (meth) acrylate, dimethylol tricyclodecane di (meth) acrylate, ethylene glycol adduct di (meth) acrylate of bisphenol A, propylene glycol adduct di (meth) acrylate of bisphenol A Di (meth) acrylic compound such as trimethylolpropane tri (meth) acrylate, pentaerythritol tri (meth) acrylate, trimethylolpropane ethylene oxa De added tri (meth) acrylate,
Glycerin propylene oxide addition tri (meth) acrylate, tri (meth) acryl compounds such as tri (meth) acryloyloxyethyl phosphate, tetra (meth) acrylate such as pentaerythritol tetra (meth) acrylate, ditrimethylolpropanetetra (meth) acrylate Acrylate and the like.

Examples of the quinone compound include hydroquinone, p-benzoquinone, tetrachloro-p-benzoquinone and the like.

When the amount of the polyfunctional monomer is large,
The crosslink density of the polyolefin resin becomes too high and the recyclability decreases, or when extruding a foamable sheet from an extruder to obtain a laminated sheet, a high load is applied to the extruder or melt fracture occurs. Or, if less, it may not be possible to impart the required elongation stress during foaming to the polyolefin resin, so 0.05 to 5 parts by weight to 100 parts by weight of the polyolefin resin is preferable. , 0.2 to 2 parts by weight.

When the polyolefin resin and the polyfunctional monomer are melted and kneaded, if the resin temperature is high, the polyolefin resin may be decomposed, and if the resin temperature is low, the polyolefin resin is not sufficiently modified. Since the elongation stress during foaming of the foamable sheet becomes insufficient and a foamed polyolefin resin sheet having a desired expansion ratio may not be obtained, the temperature is preferably 170 ° C. or more and the decomposition temperature of the polyolefin resin or less. Preferably, 200-
250 ° C. is more preferred.

Further, the fluidity of the polyolefin resin modified by the polyfunctional monomer as described above is improved at the time of foaming, so that the foaming pressure required for foaming is further reduced and the aspect ratio within the desired range described later is improved. In order to more reliably obtain a foamed polyolefin-based resin sheet having spindle-shaped cells having the following, it is preferable to further add an unmodified polyolefin-based resin to the modified polyolefin-based resin, and melt and knead. The modified polyolefin resin and the unmodified polyolefin resin may be compatible with each other, and may be the same or different.

The organic peroxide is not particularly limited as long as the polyfunctional resin can react with the polyfunctional monomer. Examples of the organic peroxide include benzoyl peroxide, 2,4-dichlorobenzoyl peroxide, and t-butyl. Peroxyacetate, t-butylperoxybenzoate, dicumyl peroxide, 2,5
-Dimethyl-2,5-di (t-butylperoxy) hexane, di-t-butyl peroxide, 2,5-dimethyl-2,5-di (t-butylperoxy) -3-hexyne and the like. And dicumyl peroxide, 2,5-dimethyl-2,5-di (t-butylperoxy) hexane, and 2,5-dimethyl-2,5-di (t-butylperoxy) -3-hexyne. preferable. The above organic peroxides may be used alone or in combination.

When the amount of the above-mentioned organic peroxide is large, when the polypropylene is used as the polyolefin-based resin, the so-called β-cleavage remarkably occurs, and the molecular weight of the modified polyolefin-based resin obtained is too low, so that the polyolefin is too low. Insufficient foaming may occur due to a decrease in the physical properties or fluidity of the resin, and if the amount is small, the polyolefin resin may be insufficiently modified with the polyfunctional monomer. 0.001 to 0.5 part by weight, preferably 0.005 to
0.15 parts by weight is more preferred.

As a second method for imparting a crosslinked structure to the polyolefin resin, a predetermined amount of a crosslinking aid is added to the polyolefin resin, and then the polyolefin resin is irradiated with a predetermined amount of ionizing radiation. To give a cross-linked structure to the polyolefin resin.

The crosslinking assistant is not particularly limited as long as it is used at the time of crosslinking of the polyolefin resin. For example, o-divinylbenzene, m-divinylbenzene, p-divinylbenzene, Examples include methylolpropane trimethacrylate, 1,9-nonanediol dimethacrylate, 1,10-decanediol dimethacrylate, triallylic acid triallyl ester, triallyl isocyanurate and the like. The crosslinking aids may be used alone or in combination.

If the amount of the crosslinking aid is large, the crosslink density of the polyolefin resin becomes too high and the foaming property may be reduced. On the other hand, if the amount is small, the crosslink density of the polyolefin resin is low and uniform. 0.1 to 10 parts by weight, preferably 0.3 to 5 parts by weight, based on 100 parts by weight of the polyolefin resin, because a suitable foam may not be obtained.

The degree of crosslinking by ionizing radiation is as follows:
It is adjusted using the gel fraction as a guide. As this gel fraction, if it is large, the moldability of the laminated sheet may be reduced, and if it is small, the bending strength of the laminated sheet may be reduced, which is preferable. Is adjusted to be 15 to 70% by weight, more preferably 18 to 65% by weight, and the ionizing radiation dose is usually 1 to 20 Mrad. The ionizing radiation is not particularly limited as long as it is conventionally used for crosslinking of the foam.
α rays, β rays, γ rays, electron beams and the like.

In the present invention, the gel fraction refers to a value measured by the following method. First, a predetermined amount of a polyolefin resin foam sheet is weighed, immersed in 25 ml of xylene at 120 ° C. for 24 hours, filtered through a 200-mesh stainless steel wire mesh, and the insoluble matter on the wire mesh is vacuum-dried. Next, the weight of the vacuum-dried insoluble matter is weighed, and the gel fraction is calculated by the following equation. [Gel fraction (%)] = (Vacuum dry weight of insoluble matter / weight of weighed thermoplastic resin foam sheet) × 100

As described above, the polyolefin resin is provided with an appropriate crosslinked structure and has fluidity and elongation pressing force within the desired ranges, and the resulting laminated sheet has excellent moldability and surface properties. Become.

Further, an inorganic filler may be added to the foamed sheet in order to improve the bending strength and the compressive strength of the laminated sheet. Examples of such an inorganic filler include metal such as titanium oxide. Oxides, calcium carbonate, talc, kaolin clay, powdered inorganic fillers such as mica, shirasu balun, glass balun, balun-like inorganic fillers such as fly ash balun and the like, among these, for improving the rigidity to polyolefin-based resin Great effect,
Talc or mica is preferred from the viewpoint that the obtained laminated sheet has excellent dimensional stability.

If the size of the inorganic filler is large, the foam may break during foaming of the foamable sheet, and a foamed sheet having a high expansion ratio may not be obtained. Those having a particle size of 20 μm or less are preferred, and those having a particle size of 5 μm or less are more preferred. Further, when the aspect ratio of the inorganic filler is large, the bending elastic gradient of the obtained polyolefin resin foam sheet is improved,
5 or more is preferred.

When the amount of the inorganic filler is large, the lightness of the obtained laminated sheet is reduced, and when the amount is small, the bending rigidity and the compressive strength of the obtained laminated sheet are reduced.
1-1 for 100 parts by weight of the polyolefin resin
00 parts by weight is preferable, and 5 to 30 parts by weight is more preferable.

Further, an antioxidant such as 2,6-di-t-butyl-p-cresol and dilaurylthiopropionate and a metal inhibitor such as methylbenzotriazole are added to the foamed polyolefin resin sheet. May be.

Most of the cells of the foamed polyolefin resin sheet are formed in a spindle shape (rugby ball shape) in which the length direction is directed to the thickness direction of the foamed polyolefin resin sheet. By orienting most of the cells of the polyolefin-based resin foam sheet in a state where the length direction thereof is oriented in the thickness direction of the polyolefin-based resin foam sheet, the above-mentioned polyolefin-based resin foam sheet is oriented in its thickness direction. Therefore, a large pressing force is applied to the polyolefin-based resin foam sheet in the thickness direction, as in the case where the laminated sheet is deep drawn and formed into a molded article having a complicated shape. Even in such a case, the polyolefin-based resin foam sheet hardly crushes in its thickness direction, and generally retains its thickness before molding. Therefore, it is not necessary to increase the thickness of the polyolefin resin foam sheet of the laminated sheet in consideration of the amount of crushing during molding, and to reduce the thickness of the polyolefin resin foam sheet by reducing the thickness of the polyolefin resin foam sheet. Can be planned.

Further, since the cells adjacent to each other in the polyolefin resin foam sheet do not interfere with each other with respect to the deformation in the thickness direction of the polyolefin resin foam sheet, the cells in the thickness direction of the polyolefin resin foam sheet do not interfere with each other. The bubbles can be smoothly and reliably displaced from each other in the thickness direction of the polyolefin resin foam sheet in response to the molding stress applied to the polyolefin resin foam sheet. The shape can be accurately and reliably formed.

If the aspect ratio (Dz / Dxy) of the cells of the foamed polyolefin resin sheet is small, the compressive strength in the thickness direction of the resulting foamed polyolefin resin sheet is reduced, so that it is limited to 1.2 or more. 1.5 or more is preferable, and 2 or more is more preferable.

The aspect ratio (Dz / Dxy) of the cells of the foamed polyolefin resin sheet is measured in the following manner. That is, first, the polyolefin resin foam sheet is cut in its thickness direction, and the length Dz in the thickness direction of the polyolefin resin foam sheet and the thickness direction of the polyolefin resin foam sheet in the cross section of the cells exposed on the cut surface are measured. The length Dxy perpendicular to the cut surface and along the cut surface is measured to calculate the aspect ratio (Dz / Dxy) of each bubble. Then, the average value of the aspect ratios (Dz / Dxy) of the obtained cells is calculated, and the aspect ratio (Dz / D) of the cells of the polyolefin resin foam sheet is calculated.
xy). In the above measurement, the bubbles to be measured are only bubbles in a completely independent state without being connected to adjacent bubbles on the cut surface, and, for example, adjacent bubbles on the cut surface face each other. Bubbles that are connected and integrated at a portion or bubbles whose ends reach the surface of the polyolefin resin foam sheet are excluded from the measurement target.

When the expansion ratio of the foamed polyolefin resin sheet is high, the mechanical strength such as the compressive strength and bending strength of the obtained laminated sheet decreases, and when the expansion ratio is low, the lightweight property of the obtained laminated sheet decreases. 5-50cm ³ /
g is preferable, and 10-30 cm < ³ > / g is more preferable.
The expansion ratio of the polyolefin resin foam sheet is measured according to JIS K6767, and is the reciprocal of the apparent density.

If the polyolefin resin foam sheet has a low compressive strength, the maximum bending strength of the polyolefin resin foam sheet will also be low, so that when a laminated sheet is processed or used as an interior material for a vehicle, an operator mistakenly laminates the sheet. The sheet may be bent and broken, or it may be bent or deformed when the laminated sheets are stacked, or when it is attached to an automobile using screws as a vehicle ceiling material, the screws may cause 9.8 N / c, since the laminated sheet of may dent and the mounting stability may be impaired.
m ² or more, more preferably 14.7 N / cm ² or more, 29.4 N / cm ² or more is more preferable.

The compressive strength used in the present specification is a value indicating resistance to a compressive force applied in a thickness direction, and is a value measured according to JIS K7220.

In the above-mentioned polyolefin resin foam sheet, liquid crystal resin fibers may be dispersed preferably in a state where the length direction thereof is oriented in the thickness direction of the polyolefin resin foam sheet. Further, the compressive strength of the polyolefin resin foam sheet can be improved by adding liquid crystal resin fibers to the polyolefin resin foam sheet. Note that, as the liquid crystal resin fiber, the same as the liquid crystal resin fiber dispersed in the polyolefin resin sheet described later is used, and the description is omitted here.

At this time, if the content of the liquid crystal resin fibers in the above-mentioned polyolefin resin foam sheet is large, foaming of the foamable sheet which becomes the raw material of the polyolefin resin foam sheet is inhibited, and the polyolefin resin fiber having a high expansion ratio is prevented. A resin foam sheet cannot be obtained, and the lightness of the obtained laminated sheet may be reduced.If the amount is too small, the effect of including the liquid crystal resin fiber is not exhibited, so that the
30% by weight is preferred.

Further, in the laminated sheet of the present invention, a polyolefin resin sheet having liquid crystal resin fibers dispersed on both sides of the polyolefin resin foam sheet, preferably, the liquid crystal resin fibers are oriented in one direction along the surface direction. The polyolefin-based resin sheets dispersed in this state are laminated and integrated. As described above, the bending strength and dimensional stability of the laminated sheet can be improved by laminating and integrating the polyolefin resin sheet in which the liquid crystal resin fibers are dispersed on both sides of the polyolefin resin foam sheet.

Further, a plurality of polyolefin resin sheets in which the liquid crystal resin fibers are dispersed in one direction along the surface direction are provided on each of both sides of the polyolefin resin foam sheet. Anisotropy can be prevented from occurring in the bending strength of the laminated sheet obtained by laminating and integrating the liquid crystal resin fibers dispersed in the sheet in a state in which the orientation directions of the liquid crystal resin fibers are different.

The polyolefin resin sheets laminated and integrated on both sides of the polyolefin resin foam sheet may be of different types, but from the viewpoint of dimensional stability of the resulting laminated sheet, It is preferable to use the same type of sheet to be laminated and integrated on both sides of the foam sheet.

Examples of the polyolefin resin constituting the polyolefin resin sheet include polyethylene such as low-density polyethylene, linear low-density polyethylene, medium-density polyethylene, and high-density polyethylene, isotactic polypropylene, syndiotactic. Polypropylene such as polypropylene, polybutene, ethylene-
α-olefin copolymer, ethylene-propylene-diene terpolymer, ethylene-vinyl acetate copolymer and the like, preferably polyethylene or polypropylene,
Mixtures of polyethylene and polypropylene are more preferred.

The above α-olefin includes propylene, 1-butene, 1-pentene, 1-hexene,
-Methyl-1-pentene, 1-heptene, 1-octene, and the like. Examples of the copolymer containing an ethylene component include a block copolymer, a random copolymer, and a random block copolymer. There may be.

The melt viscosity of the polyolefin resin is as follows:
If it is large, the viscosity difference between the polyolefin-based resin and the liquid crystal resin becomes too large, and it may not be possible to mix the two evenly.If it is small, the shear stress or the elongation stress is sufficiently transmitted to the liquid crystal resin. In some cases, the liquid crystal resin cannot be uniformly dispersed in the polyolefin resin, or the liquid crystal resin cannot be formed into a fibrous form.
is preferred, and 2,000-6,000 poise
Is more preferred. The polyolefin resin has a melt viscosity of 290 at a temperature in accordance with JIS K7199.
C., measured at a shear rate of 100 / sec.

The liquid crystal resin constituting the liquid crystal resin fibers dispersed in the polyolefin resin sheet is not particularly limited as long as it can be made into a fibrous form.
Examples thereof include wholly aromatic liquid crystal resins such as thermoplastic liquid crystal polyester and thermoplastic polyester amide. Specifically, the wholly aromatic liquid crystal resin is a trade name “Vectra” from Polyplastics and a trade name “Zyder” from Amoco.
Sold in.

When the liquid crystal resin fiber has a small aspect ratio (fiber length / fiber diameter), the mechanical strength of the resulting polyolefin resin sheet may be reduced.
1.5 or more is preferable, 50 to 5,000 is preferable,
100-3,000 is more preferable.

Further, as the diameter of the liquid crystal resin fiber increases, the dispersibility of the liquid crystal resin fiber in the polyolefin resin sheet decreases, and the mechanical strength of the polyolefin resin sheet decreases. Therefore, the diameter is preferably 10 μm or less. .

If the content of the liquid crystal resin fibers in the polyolefin resin sheet is large, the liquid crystal resin fibers may not be uniformly dispersed in the polyolefin resin. Since the reinforcing effect of the polyolefin-based resin sheet by the fiber may be insufficient, it is preferably 0.1 to 60 parts by weight, more preferably 1 to 30 parts by weight, and more preferably 3 to 20 parts by weight based on 100 parts by weight of the polyolefin-based resin. Parts are particularly preferred.

Further, the above-mentioned polyolefin resin sheet is treated at a temperature higher than the glass transition temperature of the liquid crystal resin fibers, preferably at a temperature higher than 200 ° C. in an inert gas stream such as nitrogen or under vacuum to solid-state polymerize the liquid crystal resin. Alternatively, the liquid crystal resin may be made infusible by addition-polymerizing a bifunctional compound such as an oxazoline derivative at the terminal carboxyl group to extend the chain. Thus, the mechanical strength of the polyolefin resin sheet can be improved by making the liquid crystal resin infusible.

Further, a compatibilizer may be added to the polyolefin resin sheet in order to improve the compatibilization between the polyolefin resin and the liquid crystal resin fiber constituting the sheet. Is, for example, a copolymerized polyester comprising a p-hydroxybenzoic acid residue unit and an ethylene terephthalate unit, which is a constituent unit having an aliphatic skeleton, disclosed in JP-B-56-18016 and JP-A-1-26632. And the like, and an acid-modified polyolefin-based resin obtained by subjecting a monomer unit having an acid component to a polyolefin-based resin to block copolymerization, random copolymerization, or graft copolymerization.
The semi-aromatic liquid resin is specifically sold by Sumitomo Chemical Co., Ltd. under the trade name "Econol", and by Unitika Ltd. under the trade names "Rodrun" and "LC-5000".

When the content of the structural unit having an aliphatic skeleton, which is a component of the semi-aromatic liquid crystal resin, is large, the mechanical strength of the polyolefin resin sheet obtained by reducing the mechanical strength of the semi-aromatic liquid crystal resin is reduced. Target strength is reduced, or
The compatibility with the wholly aromatic liquid crystal resin may decrease,
On the other hand, if the amount is small, the compatibility with the polyolefin resin may be reduced.

Examples of the monomer having an acid component that modifies the acid-modified polyolefin resin include (meth) acrylic acid, maleic anhydride and alkyl esters such as methyl ester, ethyl ester and glycidyl ester thereof. Can be

When the amount of acid modification of the acid-modified polyolefin resin is large, the particle size of the liquid crystal resin dispersed in the polyolefin resin becomes too small, and the stress from the polyolefin resin is effectively applied to the liquid crystal resin. Not communicated,
The liquid crystal resin may not be fibrous, and if the amount is small, the polyolefin resin and the liquid crystal resin do not compatibilize with each other, causing interfacial delamination between the two, and lowering the mechanical strength of the obtained polyolefin resin sheet. Because
0.01 to 10% by weight is preferred.

When the weight-average molecular weight of the acid-modified polyolefin resin is too large, the molecular chain of the acid-modified polyolefin resin is too long to intervene between the polyolefin resin and the liquid crystal resin. In some cases, the polyolefin resin and the liquid crystal resin do not compatibilize with each other, causing interfacial separation therebetween, resulting in a decrease in the mechanical strength of the resulting polyolefin resin sheet. The viscosity of the resin decreases, and the acid-modified polyolefin resin cannot be efficiently interposed between the polyolefin resin and the liquid crystal resin. And the mechanical strength of the resulting polyolefin-based resin sheet may be reduced.

When the content of the compatibilizer in the polyolefin resin sheet is large, the mechanical strength of the polyolefin resin sheet may be reduced, and when the content is small, the polyolefin resin and the liquid crystal resin may be reduced. And the mechanical strength of the resulting polyolefin-based resin sheet may decrease, so that 0.1 to 5 parts by weight of the polyolefin-based resin and the liquid crystal resin fiber is 0.1 to 5 parts by weight based on the total amount of 100 parts by weight. preferable.

In the polyolefin resin sheet, a bromine flame retardant such as hexabromobiphenol ether, decabromodiphenyl ether, etc., ammonium polyphosphate, trimethyl phosphate, triethyl phosphate may be used as long as the physical properties of the polyolefin resin sheet are not impaired. And other additives such as phosphorus-containing flame retardants, melamine derivatives, inorganic flame retardants, etc., fillers, antioxidants, nucleating agents, pigments and the like.

Next, a method of manufacturing the laminated sheet will be described. First, a method for producing the polyolefin resin sheet of the laminated sheet will be described. The method for producing the polyolefin-based resin sheet is not particularly limited. For example, the polyolefin-based resin and the liquid crystal resin are supplied to a general-purpose melt-kneading unit such as an extruder or a kneader, and the liquid crystal transition temperature of the liquid crystal resin or higher is supplied. In, after adding a compatibilizer at any timing as needed, melt-kneading and uniformly dispersing the liquid crystal resin in the polyolefin resin,
By applying a shear stress and an elongation stress to the polyolefin resin in which the liquid crystal resin is dispersed by any method, the liquid crystal resin is formed into a liquid crystal resin fiber oriented in a certain direction, and is formed into a sheet to form the polyolefin resin. A method for producing a sheet is included. The liquid crystal transition temperature of the liquid crystal resin means a temperature at which the liquid crystal resin changes from a solid phase to a liquid crystal state.

When the shear rate applied to the polyolefin-based resin and the liquid crystal resin by the melt-kneading means is high, the liquid crystal resin is excessively dispersed in the polyolefin-based resin and has a sufficient aspect ratio. In some cases, fibers cannot be obtained, and when low, the shear stress applied to the polyolefin-based resin is not sufficiently transmitted to the liquid-crystal resin, and the liquid-crystal resin is not uniformly dispersed in the polyolefin-based resin. Therefore, 1 × 10 ⁻¹ to 1 × 10 ⁴ sec ⁻¹ is preferable, and 1 × 10 ⁻¹ to 1 × 10 ⁴ sec ⁻¹ is preferable.
10 ^-1 to 1 × 10 ³ sec ^-1 is more preferable.

Further, as a method of applying a shear stress and an elongation stress to the polyolefin resin in which the liquid crystal resin is dispersed to make the liquid crystal resin into a fibrous form, for example, the shearing of the liquid crystal resin by melt kneading in an extruder is performed. A method of applying a stress and an elongation stress to make the liquid crystal resin into a fibrous form,
When the liquid crystal resin passes through the mold attached to the extruder, a method of applying shear stress and elongation stress to the liquid crystal resin to make the liquid crystal resin into a fibrous form, the method extruded from the mold attached to the extruder, The polyolefin-based resin sheet is stretched by pulling the polyolefin-based resin sheet at a speed higher than the extrusion speed from the mold, and the liquid crystal resin contained in the polyolefin-based resin sheet is subjected to a shearing stress and an elongational stress to give a liquid crystal. A method in which the resin is made into a fibrous form is exemplified.

When the shear stress and the elongation stress applied when the liquid crystal resin is made into a fibrous form by the above-mentioned method are large, the polyolefin resin sheet itself may be cut. 1 × 10 ⁻¹ to 1 × 10 ⁵ sec ⁻¹ is preferable, and 3 × 10 ¹ to 1 × 10 ⁴ sec ⁻¹ is more preferable because the resin does not sometimes become fibrous.

The method for producing the laminated sheet is not particularly limited. For example, a polyfunctional monomer is added to a polyolefin resin, and the modified polyolefin resin is reacted with the polyolefin resin to form a modified polyolefin resin. The foamed sheet is formed by adding a pyrolytic foaming agent to the modified polyolefin resin and melt-kneading at a temperature lower than the decomposition temperature of the pyrolytic foaming agent to form a foamable sheet. After laminating the polyolefin-based resin sheet to form a foamable laminated sheet, the foamable laminated sheet is heated to a temperature higher than the reaction temperature of the polyfunctional monomer and the decomposition temperature of the pyrolytic foaming agent, and substantially in the thickness direction. PROCESS FOR PRODUCING A LAMINATE SHEET FOR FOAMING ONLY ONLY AND INTEGRATING THE POLYOLEFIN RESIN SHEET AND POLYFINE RESIN FOAM SHEET A foamable resin composition containing a polyolefin-based resin, a crosslinking aid and a pyrolytic foaming agent is melt-kneaded at a temperature lower than the reaction temperature of the crosslinking aid and the decomposition temperature of the pyrolytic foaming agent. Formed into
After imparting a crosslinked structure to the foamable sheet by irradiating the foamable sheet with ionizing radiation, after forming the foamable laminated sheet by laminating the polyolefin-based resin sheet on both sides of the foamable sheet, A method for producing a laminated sheet in which the foamable laminated sheet is heated to a temperature not lower than the decomposition temperature of the thermal decomposition type foaming agent to foam substantially only in the thickness direction and to integrate the polyolefin resin sheet and the polyolefin resin foam sheet. A modified polyolefin resin is produced by adding a polyfunctional monomer to the polyolefin resin and reacting the polyfunctional monomer with the polyolefin resin, and then adding a pyrolytic blowing agent to the modified polyolefin resin. Melt-kneading at a temperature lower than the decomposition temperature of the pyrolytic foaming agent to produce a foamable sheet,
While the obtained foamable sheet is sandwiched between the opposing surfaces of the pair of plate-like bodies, the distance between the opposing surfaces of the pair of plate-like bodies is gradually increased while heating to a temperature equal to or higher than the decomposition temperature of the pyrolytic foaming agent. Spread and expand the foamable sheet substantially only in the thickness direction to produce a polyolefin resin foam sheet, while supplying the polyolefin resin and the liquid crystal resin to an extruder to obtain a liquid crystal transition temperature of the liquid crystal resin or higher. Then, the polyolefin-based resin sheet was extruded from a mold attached to an extruder after melt-kneading while adding a compatibilizer at any timing as necessary to uniformly disperse the liquid crystal resin in the polyolefin-based resin. Thereafter, the liquid crystal resin in the polyolefin-based resin sheet is made into a fibrous form by drawing at a speed higher than the extrusion speed to produce a polyolefin-based resin sheet. A method for producing a laminated sheet in which a polyolefin resin sheet is extruded and laminated on both sides of the polyolefin resin foam sheet, a modified polyolefin by adding a polyfunctional monomer to the polyolefin resin and reacting the polyfunctional monomer with the polyolefin resin. To produce a foamable sheet by adding a thermal decomposition type foaming agent to the modified polyolefin resin and melt-kneading at a temperature lower than the decomposition temperature of the thermal decomposition type foaming agent,
While the obtained foamable sheet is sandwiched between the opposing surfaces of the pair of plate-like bodies, the distance between the opposing surfaces of the pair of plate-like bodies is gradually increased while heating to a temperature equal to or higher than the decomposition temperature of the pyrolytic foaming agent. Spread and expand the foamable sheet substantially only in the thickness direction to produce a polyolefin resin foam sheet, while supplying the polyolefin resin and the liquid crystal resin to an extruder to obtain a liquid crystal transition temperature of the liquid crystal resin or higher. Then, the polyolefin-based resin sheet was extruded from a mold attached to an extruder after melt-kneading while adding a compatibilizer at any timing as necessary to uniformly disperse the liquid crystal resin in the polyolefin-based resin. Then, the liquid crystal resin in the polyolefin-based resin sheet is made into a fibrous form by drawing at a speed higher than the extrusion speed to produce a polyolefin-based resin sheet. A method for producing a laminated sheet by extruding and laminating a polyolefin resin foam sheet on one side of the polyolefin resin foam sheet to produce a pair of laminated foam sheets, and thermally fusing the polyolefin resin foam sheets of the pair of laminated foam sheets to each other The above-described method for producing a laminated sheet is preferable because the strain present in the obtained laminated sheet is reduced and the moldability is improved.

The plate used in the above-mentioned manufacturing method is provided with a large number of fine suction holes, and the foamable sheet is sucked from the suction holes to oppose the pair of plate members. It is preferable that the foamable sheet is not detached from the surface.

In the case where the liquid crystal resin fibers are dispersed in the foamed polyolefin resin sheet in a state of being oriented in the thickness direction of the foam sheet, the method for producing a foamed polyolefin resin sheet may include the steps of: Further, a predetermined amount of polyolefin-based resin pellets containing liquid crystal resin fibers obtained by the following method may be added.

The method for producing the above-mentioned polyolefin-based resin pellets is as follows. In the procedure for producing the above-mentioned polyolefin-based resin sheet, instead of being formed into a sheet, it is formed into a strand and cut into a predetermined length. Can be.

Then, a method for producing the above laminated sheet
In all the steps, it is preferable that the temperature is adjusted so as to be lower than the liquid crystal transition temperature of the liquid crystal resin. This is because when the temperature becomes higher than the liquid crystal transition temperature of the liquid crystal resin, the aspect ratio of the liquid crystal resin fiber decreases, the fiber form of the liquid crystal resin fiber disappears, or the orientation of the liquid crystal resin fiber is relaxed. Because there is.

Further, in the above method for producing a laminated sheet, after the polyolefin resin sheet is extruded and laminated on one side of the polyolefin resin foam sheet, the polyolefin resin sheet and the polyolefin resin foam sheet are immediately cooled. Preferably, the cooling temperature at that time is (the melting point of the polyolefin resin constituting the polyolefin resin sheet-120 ° C).
To (melting point of polyolefin resin constituting the polyolefin resin sheet −40 ° C.).

If the temperature is higher than (the melting point of the polyolefin resin constituting the polyolefin resin sheet −40 ° C.), heat may be transferred to the polyolefin resin foam sheet, and the polyolefin resin foam sheet may be sagged. Further, if it is lower than (the melting point of polyolefin resin constituting the polyolefin resin sheet -120 ° C),
This is because the difference in shrinkage ratio between the polyolefin-based resin foam sheet and the polyolefin-based resin sheet may increase, and the two may be separated from each other.

In the above-described method for producing a laminated sheet, when extruding and laminating a polyolefin-based resin sheet on one side of a polyolefin-based resin foamed sheet, both are sandwiched from both sides. Before sandwiching, the polyolefin resin foam sheet may be crushed in the thickness direction, and if it is low, the integration of the polyolefin resin foam sheet and the polyolefin resin sheet may be insufficient. It is preferable to sandwich the polyolefin-based resin foam sheet and the polyolefin-based resin sheet so that the total thickness is 30 to 60%.

The pyrolytic foaming agent is not particularly limited as long as it is widely used in the production of foams. Sodium bicarbonate, ammonium carbonate,
Inorganic pyrolytic foaming agents such as ammonium bicarbonate and azide compound, azodicarbonamide, azobisisobutyronitrile, dinitrosopentamethylenetetramine, benzenesulfonylhydrazide, toluenesulfonylhydrazide, 4,4-oxybis (benzenesulfonylhydrazide) ), Organic thermal decomposition type foaming agents such as barium azodicarboxylate, trihydrazinotriazine and p-toluenesulfonyl semicarbazide.

If the amount of the foaming agent is large, the foam may be broken. If the amount is small, the foam may not be foamed.
~ 50 parts by weight are preferred.

As a method for heating the foamable laminated sheet or the foamable sheet, a general-purpose heating apparatus conventionally used for producing a foamed body is used. A roll-type heating device or a belt-type heating device for supplying a foamable laminated sheet or a foamable sheet between heating rolls or heating belts to heat the foamable laminated sheet or the foamable sheet, a foamable laminated sheet or a foamable sheet Oil bath, metal bath, salt bath, etc., for hot-bathing a hot air bath that blows hot air onto a foamed laminated sheet or a foamable sheet.

When the foamable sheet is foamed in the above manner, the foamable sheet is foamed because a polyolefin resin sheet or a plate-like body is laminated on one surface of the foamable sheet. Is suppressed by the polyolefin-based resin sheet or the plate-like body, while foaming in the thickness direction is in a free-foamed state without being suppressed by the polyolefin-based resin sheet or the plate-like body.

The foaming direction of the foamable sheet is regulated so as to be oriented in the thickness direction. The foam of the polyolefin resin foam sheet obtained by foaming the foamable sheet has the same length as the foamed sheet. The direction is oriented in the thickness direction of the foamable sheet (polyolefin resin foam sheet), and is formed into a spindle shape having an aspect ratio (Dz / Dxy) within a predetermined range.

Accordingly, most of the cells of the foamed polyolefin resin sheet are formed in a spindle shape with the length direction oriented in the thickness direction of the foamed polyolefin resin sheet. It is formed from a foamed resin sheet and has excellent compressive strength in the thickness direction while maintaining lightness.
Moreover, the laminated sheet is provided on one side of the foam sheet.
Since the polyolefin resin sheet is laminated and integrated, it has excellent bending strength.

Further, since the above-mentioned laminated sheet is formed by laminating and integrating a polyolefin-based resin sheet on one side of a polyolefin-based resin foam sheet having excellent moldability, a hot press for performing heat-molding with a general compression molding machine. Method, heating above the softening point of the foamed sheet, specifically, heating the surface temperature of the laminated sheet to 160-210 ° C, and then maintaining the temperature below the softening point of the foamed sheet, specifically, 10-70 ° C. It can be formed into a desired shape by a general-purpose molding method such as a cold press method or a vacuum molding method in which shape transfer is performed in the formed male and female molds.

When the heating temperature of the laminated sheet in the cold press method is high, the foamed polyolefin resin sheet of the laminated sheet is melted and the aspect ratio of the cells in the foamed polyolefin resin sheet is reduced, so that the molded article obtained is Compressive strength may decrease, and if low,
Insufficient molding of the laminated sheet may not be possible to form into the desired shape, or molding distortion may remain in the resulting molded product and the dimensional stability of the molded product may be reduced.
160-210 ° C is preferred.

If the heating temperature of the male and female molds in the above cold press method is high, the resulting molded article may be insufficiently cooled and the dimensions of the molded article may change with time. The molding temperature is preferably from 10 to 70 ° C., because the molding of the molded product cannot be formed into a desired shape due to insufficient molding, or molding distortion may remain in the obtained molded product to reduce the dimensional stability of the molded product. .

[0094]

The liquid crystal resin fibers dispersed in the polyolefin resin sheet of the laminated sheet of the present invention are flexible and pliable, and the liquid crystal transition temperature of the liquid crystal resin constituting the same is higher than the melting point of the polyolefin resin. Therefore, even when the laminated sheet is heated to a molding temperature, that is, near the melting point of the polyolefin-based resin, the liquid crystal resin fibers of the polyolefin-based resin sheet are molded without decreasing the aspect ratio. It reliably maintains the previous fiber form and deforms smoothly along the molded shape without breaking.

Moreover, the foamed polyolefin-based resin sheet of the laminated sheet has excellent compressive strength in the thickness direction because the bubbles are oriented in the length direction in the thickness direction of the foamed sheet. Even if a large compressive force is applied in the thickness direction when forming the laminated sheet, the polyolefin resin foam sheet is not crushed in the thickness direction and the thickness does not decrease, and the thickness before molding is substantially ensured. To hold.

Accordingly, the laminated sheet can be formed into a complicated shape with sufficient shaping force while the polyolefin resin foam sheet and the polyolefin resin sheet are sufficiently heated.

The liquid crystal resin fibers in the polyolefin resin sheet in the obtained molded product are deformed into a desired shape while reliably maintaining the shape before molding without breaking. The foamed resin sheet substantially retains its thickness before molding even after molding, and thus the molded article obtained is excellent in bending strength, compressive strength and dimensional stability.

[0098] In addition, as described above, the polyolefin resin foam sheet of the laminated sheet has excellent compressive strength in the thickness direction and has almost no decrease in thickness at the time of molding. It is not necessary to increase the thickness in consideration of the thickness reduction, and therefore, the thickness of the polyolefin resin foam sheet before molding can be reduced,
The lightness of the molded product can be improved.

Further, in the conventional laminated sheet, since the inorganic fiber is used for reinforcing the laminated sheet, it is necessary to separate the inorganic fiber from the resin component at the time of disposal. Inorganic fibers were cut inside and the aspect ratio was lowered, and the mechanical strength before recycling could not be exhibited.

However, even if the liquid crystal resin fibers dispersed in the polyolefin resin sheet of the laminated sheet are cut during the recycling process, the liquid crystal resin fibers are re-melted and applied with a shear stress and an elongation stress to have a sufficient aspect ratio again. It can be reused as a liquid crystal resin fiber having
Therefore, the laminated sheet is excellent in recyclability and environment.

[0101]

EXAMPLES (Example 1) The following equipment was used to produce a foamable polypropylene sheet. That is, a co-rotating twin screw extruder (Plastic Engineering Laboratory Co., Ltd.)
A co-rotating twin screw extruder (trade name "TEX-4" manufactured by Nippon Steel Works Co., Ltd.) via an adapter at the tip of a trade name "BT40" (hereinafter referred to as "first extruder").
4 ", hereinafter referred to as" second extruder ").

The first extruder was equipped with a self-wiping double screw, and had an L / D of 35 and a D (diameter) of 39 m.
m. The cylinder barrel is divided from the first barrel to the fourth barrel from the upstream to the downstream of the extruder, and the tip of the fourth barrel can be continuously connected to a TEX-44 type co-rotating twin screw extruder described later. An adapter is provided.

[0103] A vacuum vent is provided in the fourth barrel in order to recover components volatilized in the cylinder barrel, in particular, a modifying monomer. In the following operation, the temperature of the first barrel of the first extruder was set to 180 ° C.,
The temperature of the barrel to the fourth barrel was set to 220 ° C., and the screw rotation speed was set to 150 rpm.

The second extruder is provided with a self-wiping double-start screw, having an L / D of 45.5 and a D of 47 m.
m. The cylinder barrel is divided into a first barrel to a twelfth barrel from upstream to downstream of the extruder,
A coat hanger die having a width of 1500 mm is attached to the tip of the two barrels.

Further, a side feeder is provided in the sixth barrel for supplying the foaming agent, and a vacuum vent is provided in the eleventh barrel for recovering components volatilized in the cylinder barrel.

In the following operation, the first barrel of the second extruder is constantly cooled, the temperature of the second to fourth barrels is set to 150 ° C., and the temperature of the fifth to eighth barrels is set to 170 ° C.
Temperature of the ninth barrel to the twelfth barrel to 180 ° C
And the temperature of the adapter and coat hanger die to 160
° C, and the screw rotation speed was set to 40 rpm.

A random type of polypropylene (trade name “EG8”, manufactured by Nippon Polychem Co., Ltd., melt index = 0.8 g / 10 min., Density) was placed in a hopper integrally provided at the rear end of the first barrel of the first extruder. = 0.9g / cm
³ ) and p-quinone dioxime (Ouchi Shinko Chemical Co., Ltd. product name “Valnock GM-
P "), melted and kneaded to produce a modified polypropylene, and the resulting modified polypropylene was continuously supplied to a second extruder via an adapter. In addition,
The input amount of the polypropylene was 10 kg / h, and the input amount of p-quinonedioxime was 0.08 kg / h.

Further, modified polypropylene pellets obtained from a hopper provided at the rear end of the first barrel of the second extruder and unmodified homopolypropylene (trade name “EA9” manufactured by Nippon Polychem Co., Ltd .; Index = 0.5 g / min, density = 0.91 g / cm ³ ), and azodicarbonamide was supplied from a side feeder provided in the sixth barrel of the second extruder. Modified polypropylene, pellets of modified polypropylene, unmodified homopolypropylene and azodicarbonamide continuously supplied from the extruder are melted and kneaded, and then foamed to a thickness of 0.25 mm from a coat hanger die attached to the tip of the second extruder. A functional polypropylene sheet was obtained. The input amount of the modified polypropylene pellet was 10 kg / h, the input amount of the unmodified homopolypropylene was 10 kg / h, and the input amount of the azodicarbonamide was 3 kg.
/ H.

The pellets of the modified polypropylene supplied from the hopper of the first barrel of the second extruder were prepared as follows. That is, instead of the adapter used to connect the second extruder to the tip of the first extruder used above, a three-hole strand die was used instead of the adapter, and the rear end of the first barrel of the extruder was used. A random-type polypropylene (made by Nippon Polychem Co., Ltd., melt index = 0.8 g)
/ 10 min, density = 0.9 g / cm ³ ) and p-quinone dioxime (trade name “Varnock GM-P” manufactured by Ouchi Shinko Chemical Co., Ltd.) as a polyfunctional monomer, melt, knead, After extruding the modified polypropylene from a three-hole strand die, it was cooled with water, and cut into a predetermined length with a pelletizer to obtain a pellet-shaped modified polypropylene. In addition, the input amount of the above polypropylene is 10 kg / h, p-
The input amount of quinone dioxime was 0.08 kg / h.

Subsequently, the expandable polypropylene sheet was cut into a rectangular parallelepiped shape having a width of 500 mm and a length of 500 mm.
The foamable polypropylene sheet is sandwiched between a pair of iron plates held at 0 ° C., and while the foamable polypropylene sheet is heated and foamed, the distance between the pair of iron plates is gradually widened from 0.25 mm to 5 mm. A polypropylene foam sheet 1 (thickness = 5 mm, width = 500 mm, length = 5) in which foam is substantially foamed only in the thickness direction and the spindle-shaped air bubbles 11 are directed in the length direction in the thickness direction of the foam sheet.
00 mm). The expansion ratio of the obtained polypropylene foam sheet 1 was 19.8 cm ³ / g.

[0111] The iron plate has 10,000 suction holes having a diameter of 0.2 mm penetrating between both surfaces thereof at 10,000 holes / m ^2.
The foamable polypropylene sheet is sucked through the suction hole to adsorb both sides of the foamable polypropylene sheet to the iron plate surface, so that the foamable polypropylene sheet is not accidentally detached from the iron plate. It is.

On the other hand, polypropylene (trade name “Novatech EA9” manufactured by Nippon Polychem Co., Ltd., melt index =
90 parts by weight (0.5 g / 10 min), 10 parts by weight, a wholly aromatic liquid crystal resin (trade name “Vectra A950”, manufactured by Polyplastics, liquid crystal transition temperature = 280 ° C.), a semi-aromatic liquid crystal resin (trade name, manufactured by Unitika) “LC-5000”) 1 part by weight and acrylic acid-modified polypropylene (UNIROYAL)
0.5 part by weight of a product name “Polybond 1002” manufactured by the company) was dry-blended.

The dry-blended product was supplied to a twin-screw extruder (trade name “PCM-30” manufactured by Ikegai Kiko Co., Ltd.), melted and kneaded at 290 ° C., and then maintained at 290 ° C. attached to the twin-screw extruder. 15 kg extruded from the extruded T die
/ H, extruding the polypropylene sheet in the molten state in the extrusion direction, and then extruding the polypropylene sheet into a pair of pressure rolls (roll interval = 110 μm, clamping pressure = 10 k).
g / cm ² , roll temperature = 60 ° C., linear velocity = 8 m / mi
n) The mixture was supplied and cooled to obtain a polypropylene sheet having a thickness of 110 μm in which liquid crystal resin fibers were dispersed, and a polypropylene sheet 2 having a width of 500 mm and a length of 500 mm was obtained from the polypropylene sheet.

When the cut end face in the thickness direction along the stretching direction of the obtained polypropylene sheet was observed with a scanning electron microscope (SEM), the wholly aromatic liquid crystal resin was in a fibrous form. Was oriented in one direction along the surface direction of the polypropylene sheet 2.

Then, the above-mentioned polypropylene foam sheet 1
After arranging the polypropylene sheet 2 in which the liquid crystal resin fibers 21 are oriented in one direction along the surface direction,
The polypropylene sheets 2 and 2 were laminated and integrated on both sides of the polypropylene foam sheet 1 by being supplied between the thermocompression rolls held by the above and sandwiched from both sides to obtain a laminated sheet A (see FIG. 1).

Example 2 70 parts by weight of polypropylene (trade name: Novatec EA9, manufactured by Nippon Polychem Co., Ltd., melt index = 0.5 g / 10 min), wholly aromatic liquid crystal resin (trade name: Vectra A95 manufactured by Polyplastics)
0 ", liquid crystal transition temperature = 280 ° C) 30 parts by weight, semi-aromatic liquid crystal resin (trade name" LC-5000 "manufactured by Unitika Ltd.)
3 parts by weight and acrylic acid-modified polypropylene (UNIR
Oyal's product name "Polybond1002")
1.5 parts by weight were dry blended.

The dry-blended product was supplied to a twin screw extruder (trade name “PCM-30” manufactured by Ikegai Kiko Co., Ltd.), melted and kneaded at 290 ° C., and extruded from a mold attached to the twin screw extruder. After being extruded into a strand having a diameter of 3 mm at an amount of 15 kg / h, the polypropylene strand was stretched in the extrusion direction in a molten state, cooled with water, and cut into a predetermined length to obtain a polypropylene pellet containing a liquid crystal resin fiber.

When the cut end face in the radial direction along the stretching direction of the obtained polypropylene pellet containing the liquid crystal resin fiber was observed with a scanning electron microscope (SEM), the wholly aromatic liquid crystal resin was in a fibrous form. The liquid crystal resin fibers were oriented in the length direction of the liquid crystal resin fiber-containing polypropylene pellets.

Then, in the same manner as in Example 1, except that the polypropylene pellet containing the liquid crystal resin fiber was supplied to a hopper provided at the rear end of the first barrel of the second extruder instead of the unmodified homopolypropylene. Sheet A was obtained.

The liquid crystal resin fibers dispersed in the foamed polypropylene sheet of the laminated sheet A are oriented so that the length direction thereof is oriented in the thickness direction of the foamed sheet.
The content of the liquid crystal resin fibers dispersed in the polypropylene foam sheet was 10% by weight, and the expansion ratio of the polypropylene foam sheet was 20.1 cm ³ / g.

(Comparative Example 1) 18 parts by weight of a glass fiber having a fiber length of 500 mm were aligned in one direction, and a polypropylene (Novatec EA9, manufactured by Nippon Polychem Co., Ltd., melt index = 0. 5g
/ 10 minutes) By supplying 82 parts by weight, melting at 180 ° C., and integrating under pressure, the glass fiber in which glass fiber oriented in one direction along the surface direction is dispersed, and has a thickness of 110 μm.
Was obtained, and a polypropylene sheet having a width of 500 mm and a length of 500 mm was cut out from the polypropylene sheet.

Then, a laminated sheet was obtained in the same manner as in Example 1 except that the polypropylene sheet in which the glass fiber was dispersed was used instead of the polypropylene sheet in which the liquid crystal resin fiber was dispersed.

Comparative Example 2 76 parts by weight of polypropylene (trade name “Novatech PP EA9” manufactured by Nippon Polychem Co., Ltd., melt index = 0.5 g / 10 min), silane crosslinkable polypropylene (trade name “LINKRON” manufactured by Mitsubishi Chemical Corporation) XPM800HM ", melt index = 10 g /
10 minutes, melting temperature = 167 ° C., 24 parts by weight of gel fraction when completely crosslinked = 80% by weight, silane crosslinking catalyst master batch (trade name “PZ-10S” manufactured by Mitsubishi Chemical Corporation, 100 parts by weight of polypropylene) Dibutyltin dilaurate 1
1.2 parts by weight of azodicarbonamide and 10 parts by weight of azodicarbonamide were supplied to a twin-screw extruder (trade name "PCM-30", manufactured by Ikegami Kiko Co., Ltd.), and the lip clearance was 3 mm and the width was 700 mm After extruding from the sheet die,
By sizing with a pair of upper and lower water-cooled triple rolls, a foamable sheet (thickness = 1.85 mm, width = 500 m)
m, length = 500 mm). The barrel temperature of the twin-screw extruder and the temperature of the sheet die were 180 ° C.

Next, the foamable sheet was immersed in hot water of 100 ° C. for 2 hours to be crosslinked, supplied into an oven maintained at 220 ° C., foamed, and then maintained at 10 ° C. Into a water tank and cooled, and the foam sheet (thickness = 5m)
m, width = 500 mm, length 500 mm). In addition,
The expansion ratio of the obtained foamed sheet is 19.7 cm ³ / g.
Met. Then, a laminated sheet was obtained in the same manner as in Comparative Example 1 except that the above foamed sheet was used.

Comparative Example 3 76 parts by weight of polypropylene (trade name “Novatech PP EA9” manufactured by Nippon Polychem Co., Ltd., melt index = 0.5 g / 10 min), silane-crosslinkable polypropylene (trade name “LINKRON” manufactured by Mitsubishi Chemical Corporation) XPM800HM ", melt index = 10 g /
10 minutes, melting temperature = 167 ° C., 24 parts by weight of gel fraction when completely crosslinked = 80% by weight, silane crosslinking catalyst master batch (trade name “PZ-10S” manufactured by Mitsubishi Chemical Corporation, 100 parts by weight of polypropylene) Dibutyltin dilaurate 1
1.2 parts by weight and 10 parts by weight of azodicarbonamide were supplied to a twin-screw extruder (trade name "PCM-30" manufactured by Ikeigai Kiko Co., Ltd.) having a lip clearance of 3 mm and a width of 700 mm. After extruding from the sheet die,
By sizing with a pair of upper and lower water-cooled triple rolls, a foamable sheet (thickness = 1.85 mm, width = 500 m)
m, length = 500 mm). The barrel temperature of the twin screw extruder and the temperature of the sheet die were set to 180 ° C.

Next, the foamable sheet was immersed in hot water at 100 ° C. for 2 hours to crosslink, and then supplied into an oven maintained at 220 ° C. for foaming. Into a water tank and cooled, foamed polypropylene sheet (thickness = 5 mm, width = 500 mm, length 500 mm)
I got The expansion ratio of the obtained polypropylene foam sheet was 19.7 cm ³ / g.

On the other hand, polypropylene (product name “Novatech EA9” manufactured by Nippon Polychem Co., Ltd., melt index =
90 parts by weight (0.5 g / 10 min), 10 parts by weight, a wholly aromatic liquid crystal resin (trade name “Vectra A950”, manufactured by Polyplastics, liquid crystal transition temperature = 280 ° C.), a semi-aromatic liquid crystal resin (trade name, manufactured by Unitika) “LC-5000”) 1 part by weight and acrylic acid-modified polypropylene (UNIROYAL)
0.5 part by weight of a product name “Polybond 1002” manufactured by the company) was dry-blended.

The dry-blended product was supplied to a twin-screw extruder (trade name “PCM-30” manufactured by Ikegai Kiko Co., Ltd.), melted and kneaded at 290 ° C., and kept at 290 ° C. attached to the twin-screw extruder. 15 kg extruded from the extruded T die
/ H, extruding the polypropylene sheet in the molten state in the extrusion direction, and then extruding the polypropylene sheet into a pair of pressure rolls (roll interval = 110 μm, clamping pressure = 10 k).
g / cm ² , roll temperature = 60 ° C., linear velocity = 8 m / mi
n) The mixture was supplied and cooled to obtain a 110-μm-thick polypropylene sheet in which liquid crystal resin fibers were dispersed, and a polypropylene sheet having a width of 500 mm and a length of 500 mm was cut out from the polypropylene sheet.

When the cut end surface in the thickness direction along the stretching direction of the obtained polypropylene sheet was observed by a scanning electron microscope (SEM), the liquid crystal resin was in a fibrous form. In one direction along the surface direction.

Then, a polypropylene sheet in which liquid crystal resin fibers are oriented in one direction along the surface direction is provided on both sides of the polypropylene foam sheet, and then supplied between thermocompression rolls maintained at 170 ° C. The polypropylene sheet was sandwiched, and the polypropylene sheet was laminated and integrated on both sides of the polypropylene foam sheet to obtain a laminated sheet.

In the laminated sheet obtained as described above, the aspect ratio of cells of the polypropylene foam sheet, the basis weight, the bending properties, the compressive strength, the linear expansion coefficient, the thermoformability and the recyclability of the laminated sheet are shown below. The measurement was carried out by the method, and the results are shown in Table 1.

(Aspect Ratio) The polypropylene foam sheet of the laminated sheet was cut in the thickness direction, and a 20-fold enlarged photograph was taken while observing the center of the cut surface with an optical microscope. With respect to the bubbles shown in the photograph, the aspect ratio (Dz / Dxy) of each bubble to be measured was measured, and the average was calculated. It should be noted that bubbles having a Dz of less than 0.1 mm or a bubble having a Dz of more than 2 mm in the actual size were also excluded from the measurement.

(Weight per unit area) The weight of the laminated sheet was measured.
It was converted to the weight per 1 m ² .

(Bending physical properties) From the laminated sheet, width 50 mm ×
A test piece having a length of 150 mm was cut out, and the test piece was subjected to a three-point bending test at a span of 100 mm and a strain rate of 50 mm / min using a jig having a fulcrum and an action point of curvature R3.2 to perform a maximum bending load and bending. The elastic gradient was measured.
The bending test was performed in the thickness direction by applying a bending jig from a direction perpendicular to the orientation direction of the fiber as a measurement direction of the bending strength. The bending test was performed five times, and the average was defined as the maximum bending load and the bending elastic gradient.

(Compression strength) Width 50 mm ×
Five rectangular parallelepiped test pieces having a length of 50 mm and a thickness of 5 mm were cut out, and the compressive strength was measured in accordance with JIS K7220. The average value of the five test pieces was defined as the compressive strength.

(Coefficient of linear expansion) Width 200 m from laminated sheet
Cut out a test piece of mx 200 mm length x 5 mm thickness,
After heating for 24 hours in an atmosphere of 85 ° C., 13
Attach a table line at 0 mm intervals. Next, the test piece was heated to 80 ° C.
After leaving it in a constant temperature bath for 6 hours, take it out and take it out (80 ° C)
(L)₈₀) Is measured. In addition,
The test specimen was left in a thermostat at 0 ° C. for 6 hours and then taken out.
The length (L) between the above table lines in degrees (0 ° C.) ₀) Measure the length
I do. Then, the linear expansion coefficient is calculated by the following equation.
Was. Linear expansion coefficient (1 / ° C) = (L₀-L₈₀) / (L₀× 8
0)

(Thermoformability) A laminated sheet A was formed using male and female molds as shown in FIG. Specifically, the female mold 3 is formed by forming a rectangular parallelepiped concave portion 32 having a length of 100 mm x a width of 100 mm x a depth of 150 mm in the center of the upper surface of a female mold body 31 having a square planar shape. Each ridge and the opening edge of the concave portion 32 are both chamfered and formed in an arc shape, while the male mold body 4 has a male mold body 41 whose female mold body of the female mold 3 is formed. It has the same shape and the same size as the mold body 31 and is formed in the shape of a plane square. The male mold body 41 has a vertical central portion on the lower surface center that can be fitted into the recess 32 of the female mold 3. A rectangular parallelepiped convex portion 42 having a size of 90 mm × 90 mm × 145 mm is protruded.

After heating the laminated sheet A to a surface temperature of 180 ° C. and disposing it between the male and female molds 3 and 4, the male and female molds 3 and 4 are closed to form the laminated sheet A. Was pressed and molded to obtain a molded product 5 having a shape as shown in FIG. The male and female molds 3 and 4 were adjusted to 40 ° C., and the closing time of the male and female molds 3 and 4 was 30 seconds. After the male and female molds 3 and 4 were opened, the obtained molded product 5 was trimmed.

Then, the cut surface in the thickness direction of the molded article 5 was observed using a scanning electron microscope (SEM), and the presence or absence of breakage of the fibers in the polypropylene sheet was observed. or,
The thickness of the molded article 5 was measured.

Further, a flat test piece having a width of 50 mm and a length of 150 mm was cut out from the molded article 5, and the fulcrum and action point of the test piece having a curvature R3.2 at a span of 100 mm and a strain rate of 50 mm / min were cut out. A maximum bending load and a bending elastic gradient were measured by performing a three-point bending test using a tool. The bending test was performed in the thickness direction by applying a bending jig from a direction perpendicular to the orientation direction of the fiber as a measurement direction of the bending strength. The bending test was performed five times, and the average was defined as the maximum bending load and the bending elastic gradient.

(Recyclability) A polypropylene sheet was peeled off from the laminated sheet, a test piece having a width of 10 mm and a length of 140 mm was cut out from the polypropylene sheet, and the tensile modulus of the test piece was measured in accordance with JIS K7113.

On the other hand, the polypropylene sheet peeled from the laminated sheet is finely cut into a width of about 5 mm and a length of about 5 mm, and then supplied to a single screw extruder. Above the temperature, otherwise melt kneading to a temperature above the melting point of the polypropylene;
After extruding the polypropylene sheet into a sheet at an extrusion rate of 15 kg / h from a T-die held at a temperature of 0 ° C., the polypropylene sheet is stretched in the extrusion direction in a molten state, and then a pair of pressure rolls (roll interval = 110 μm, clamping pressure = 10 kg) / Cm
^2. Rolls were supplied at a roll temperature of 60 ° C. and a linear velocity of 8 m / min for cooling, and a 110 μm thick polypropylene sheet was recycled.
A test piece of mm × 140 mm in length was cut out, and the tensile elasticity of the test piece was calculated according to JIS K7113, and the recyclability was calculated by the following equation.

(Recyclability) = 100 × (Tensile modulus of test piece after recycling) / (Tensile modulus of test piece before recycling)

[0144]

[Table 1]

[0145]

As described above, the laminated sheet of the present invention has excellent thermoformability and excellent bending strength, compressive strength and dimensional stability because it has the above-mentioned structure. It is suitably used for cushioning materials and the like.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a laminated sheet of the present invention.

FIG. 2 is a perspective view showing male and female molds used for measuring thermoformability.

FIG. 3 is a perspective view showing a molded product obtained by molding a laminated sheet using the male and female dies of FIG. 2;

[Explanation of symbols]

 1 polypropylene foam sheet 11 air bubbles 2 polypropylene sheet 21 liquid crystal resin fiber

 ────────────────────────────────────────────────── ─── Continued on the front page F-term (reference) JK11 JL01 JL03 JL04 YY00A

Claims (2)

[Claims] 1. A foamed polyolefin resin sheet in which spindle-shaped air bubbles having an aspect ratio (Dz / Dxy) of 1.2 or more are oriented in a state where the length direction thereof is directed in the thickness direction, is provided with liquid crystal on both surfaces. A laminated sheet wherein a polyolefin resin sheet in which resin fibers are dispersed is laminated and integrated. 2. A polyolefin resin foam sheet wherein 0.5 to 30% by weight of liquid crystal resin fibers are dispersed in a state where the length direction thereof is oriented in the thickness direction of the foam sheet. Item 7. The laminated sheet according to Item 1.