JPS58162338A - Core material for reinforced plastic - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] This invention relates to a core material for reinforced plastics.

Fiber-reinforced thermosetting resin foams are called reinforced plastics, with a core made of low-density thermosetting resin foam between the upper and lower surface layers made of relatively high-density thermosetting resin. Reinforced plastics, which are made by laminating materials in a sandwich shape, are lightweight and have excellent properties such as workability, water resistance, and corrosion resistance, and are widely used as construction materials, ship materials, and other materials. For example, between two surface layers made of synthetic resin foam reinforced with sheet fibers, a high-density synthetic resin foam reinforced with many long fibers and a high-density synthetic resin foam reinforced with many long fibers are placed between two surface layers made of synthetic resin foam reinforced with sheet fibers. A lightweight composite material machine (Japanese Patent Laid-Open No. 55-674
49) is known. The core material of the above-mentioned known composite material is made by alternately arranging synthetic resin foams with different densities and integrally bonding them along the direction of the long fibers, resulting in uneven quality. There are drawbacks such as the strength of the pressure portion being small relative to the force in the arrangement direction.

In addition, the short edge d+ formed nonwoven fabric is impregnated with polyacrylonitrile in which microspheres containing a blowing agent such as isobutane are dispersed, and after heating, a crosslinked polyacrylonitrile polish is applied once. Also known is a molded product in which a core material is impregnated with unsaturated polyester and cured (see British Patent No. 1,427,647). The above core material uses short fiber nonwoven fabric, and due to its high porosity, the tensile strength, tear strength, and compressive elasticity recovery are low, and storage retention is poor, and the fibers and impregnating agent often It has poor workability, such as falling off and generating dust, which worsens the working environment during secondary processing.Also, it is uneconomical as it requires a large amount of unsaturated polyester during secondary processing, and the specific gravity of the reinforced plastic is high. Therefore, it is insufficient in light weight, has low bending properties, and is inferior in suitability for secondary construction such as suitability for nailing, threading, and cutting.

As a result of intensive research aimed at eliminating the drawbacks of the above-mentioned known core materials, the present inventors have provided a core material that is lightweight, has high compressive elasticity, and has good workability.

In other words, in this invention, the filament yarn of a nonwoven fabric formed from filament yarn and the intertwined portion thereof are covered with a thermosetting resin foam that can contain closed cells, and
This shear material for reinforced plastics is characterized in that voids are formed between the thermosetting resin foams with a resin impregnation allowable porosity of 20 to 40% by volume during secondary processing.

To explain a schematic cross section 1 of the core material of the present invention with reference to the drawings, ld synthetic fiber filament yarn, . The foam 8 is a thermosetting resin foam containing a large number of closed cells 4. Reference numeral 5 denotes a gap 6 formed between the foam bodies 8, into which a thermosetting resin solution during secondary processing is impregnated.

The filament yarn constituting the nonwoven fabric of this invention is 1
Ordinary synthetic fibers, such as filament threads molded from thermoplastic synthetic resins such as polyester, polyamide, polyacrylic, polyvinyl chloride, and polyolefin, and polyphenol filament threads, as well as metals, carbon, titanium, The inorganic filament yarn is formed from glass or glass, but particularly preferred is the filament yarn formed from polyethylene terephthalate or nylon. Preferably it is 1 to 5 deniers.

The nonwoven fabric is a spunpond fabric in which filament yarns are randomly arranged and overlapped, needle-punched and resin-treated as needed. The thickness and basis weight of the nonwoven fabric are not particularly limited, but to suitably achieve the present invention, the thickness is 2 to 611I1% and the basis weight is 50 to 1%.
70! is preferred.

Thermosetting resins coated on filament threads of nonwoven fabric include polyvinyl acetate/ethylene copolymer, polyvinyl acetate□ethylene-acrylic terpolymer, polyacrylic acid ester, polyurethane, methoxylated polyamide, and polyepoxide. Examples include polyvinyl acetate, unsaturated polyester, etc., and mixtures of these resins.
Ethylene copolymers and polyvinyl acetate/ethylene/acrylic terpolymers are preferred because they have good permeability to resin impregnating solvents during secondary processing and flexibility of the resulting core material.

The copolymerization ratio of the above polyvinyl acetate/ethylene copolymer is:
Vinyl acetate/ethylene = 60/40 to 85/16 (mole ratio) and a relatively low molecular weight are preferable, and physical properties of a single film formed from the copolymer are encapsulated in the thermosetting resin foam. The average diameter of the closed cells is 45-1
85μ is preferable, and if the average diameter is less than 45μ, the thickness of the core material will be small, the specific gravity will be large, and the permissible porosity for resin impregnation will decrease, making it impossible to obtain a lightweight and highly rigid reinforced plastic. If the average diameter exceeds 185 μm, the closed cells tend to burst and the compressive elastic recovery property decreases, which is not preferable.

Inorganic hollow spheres can be mixed in the thermosetting resin foam. Examples of the inorganic hollow spheres include shirasu balloons, alumina balloons, and composites of mullite and glass. Of these, shirasu balloons are particularly suitable because they have good dimensional stability during secondary processing and suitability for threading reinforced plastics. Average particle size F of the above inorganic hollow spheres! 60 to 80μ, and the particle size range is preferably 10 to 2.00μ.

The core material has voids that are impregnated with a thermosetting resin solution during secondary processing, and these voids are referred to as resin impregnation allowable voids. These resin-impregnated voids are not the closed cells of the thermosetting resin foam described above, or the closed cells that have burst and become partially connected, but the gaps that are three-dimensionally formed between the resin foams. It is a structure. The percentage of the volume of the resin-impregnable voids to the total volume of the core material is the resin-impregnable void ratio (hereinafter abbreviated as porosity), which is measured and calculated by the following method.

A sample with a width of 0.7 mm and a length of 40 cm was placed on the reference line (40 cc
) The amount of increase in water surface from the reference line when the sample is immersed in a buret filled with water until it is submerged in water (nc
c) is read, and the amount of decrease in the water surface from the reference line (mcc) when the sample is taken out after leaving it for 10 seconds and soaked in water is calculated using the following formula.

The porosity of the core material is 20-40%, and the porosity is 20%.
If it is less than that, the texture of the core material will be hard, the amount of resin impregnated in the secondary processing will be too low, the behavior will approximate the behavior of non-impregnated types such as polyurethane and hard polyvinyl chloride boards, and the flexural elasticity of reinforced plastics will decrease.

Bending strength and impact strength decrease, which is not preferable.

If the porosity exceeds 40%, the compressive elastic recovery of the core material will decrease, the volume will decrease during storage, and the amount of resin impregnated during secondary processing will increase, making it heavy and uneconomical.

Next, the method for manufacturing the core material of the present invention will be explained.

After the nonwoven fabric is impregnated with a foamable resin composition containing the thermosetting resin, it is dried to simultaneously perform foaming and crosslinking and curing of the resin.

The foamable resin composition liquid contains the above-mentioned thermosetting resin, micropearls, a thickener, and a PH regulator (for example, 7 n-i-=
A) There are ten emulsions that do this. The micropearl is a granular material in which a gas such as butane or isobutane is encapsulated in a shell material such as polyvinylidene chloride/acrylonitrile copolymer, and other commonly used foamable granular materials. The blending amount of Micropearl, for example, polyvinyl acetate/ethylene copolymer 25~
It is preferably 75 to 65 parts by weight relative to 35 parts by weight.

If the amount of Micropearl Blend 1 exceeds 75 parts by weight, the resin will fall off, resulting in poor moldability, while if it is less than 65 parts by weight, the porosity will decrease, which is undesirable. In addition, when the above-mentioned inorganic hollow particles are blended into the foamable resin composition liquid, the blending amount is 2 to 15 parts by weight per 100 parts by weight of the mixture of polyvinyl acetate/ethylene copolymer and micropearl. is appropriate.

As the above-mentioned thickener, an appropriate amount of acrylic and other known thickeners may be blended.

In order to impregnate the nonwoven fabric with the foamable resin composition liquid, a commonly known method such as a saturator or a coater is applied. The impregnation t of the above composition liquid is 50.11 parts by weight for 100 parts by weight of the nonwoven fabric.
0 parts by weight is appropriate; if it is less than 50 parts by weight, the desired thickness cannot be maintained and a core material with a predetermined porosity cannot be obtained.

Moreover, if it exceeds 110 parts by weight, the feel of the core material becomes hard, the amount of thermosetting resin liquid impregnated during secondary processing decreases, the rigidity decreases, and it is not economical. The amount of impregnation can be adjusted by adjusting the resin concentration of the foaming resin composition, viscosity, doctor clearance, and roll coater rotation ratio.

This is done using mangle aperture ratio, etc. To heat the nonwoven fabric with a predetermined impregnation amount, an ordinary steam dryer, an infrared heater,
Other known dryers can be used.

The core material having the above structure usually has a thickness of 1 to 61 mm.
n1% basis weight is 70-270%, specific gravity is 0.03-0
．． 06, but is not limited to the above range. This core material may be perforated by punching or the like.

The core material of the present invention is lightweight and has good compressive elastic recovery properties, and is suitable for conventional secondary processing methods such as hand lay-up method, spray-in method, injection molding method, injection vacuum molding method, etc.
The pultrusion method can be easily applied. The reinforced plastic fabricated by secondary processing using this core material has excellent bending strength, bending elasticity, and impact resistance, stable quality, and good workability.

Boats, ship accessories, auto parts, housing equipment,
Suitable as building materials, industrial materials, and miscellaneous goods.

This invention will be explained in detail below.

Example 1 Filament yarn made of polyethylene terephthalate (
A self-crosslinking polyvinyl acetate/ethylene copolymer emulsion (solid content concentration 50% by weight), 80 parts by weight, was added to a nonwoven fabric with a fabric weight of 80 kg formed with a single fiber thickness of 8 (1).
Micropearl (water content 30% by weight) 85 parts by weight, thickener 0.8 parts by weight, aqueous ammonia (concentration 22.5% by weight) 0
-6 parts by weight, viscosity 1200 cps (20℃)
The nonwoven fabric was impregnated with a resin composition liquid and squeezed with a mangle so that the solid content was 105 parts by weight based on 100 parts by weight of the nonwoven fabric.

This resin composition liquid-impregnated sheet was dried in a dryer at 180° C. for 100 seconds while being tentered, thereby simultaneously foaming the micropearls and curing the polyvinyl acetate/ethylene copolymer by crosslinking. The obtained core material had a basis weight of 170% and a thickness of 8.211, and the average diameter of closed cells in the resin foam was 75μ.

Next, on a glass mat with a basis weight of 450% and a thickness of 0.95 ar, a viscosity of aoo cps (25 centimeters) consisting of 70 parts by weight of isophthalic acid-based unsaturated polyester, 30 parts by weight of styrene, and methyl ethyl ketone peroxide IQMII was applied.
After uniformly impregnating 1050% of the paint with a roll and laminating the above core material on this paint, further impregnating 670% of the above paint on the core material, and laminating the above glass mat on the paint surface. , apply 1050% of the above paint to this glass mat.
A laminate (reinforced plastic) with a thickness of 5.01111 was obtained by casting and impregnating the material, leaving it at room temperature for 24 hours, then curing it for 24 hours. 2A above, materials and reinforcement f,
The performance of 7-fwaai is shown in the table.

Example 2 The same self-crosslinking polyvinyl acetate/ethylene copolymer 50 as in Example 1 was added to a nonwoven fabric with a basis weight of 90% formed from nylon filament yarn (single meter fiber thickness 1.5 d).
Parts by weight, self-crosslinking polyvinyl acetate/ethylene/acrylic terpolymer emulsion (solid content concentration 50% by weight)
, 98 parts by weight of the same micropearls as in Example 1, 5 parts by weight of Shirasu balloons, 0-8 parts by weight of thickener, 0.0 parts by weight of aqueous ammonia.
A resin composition liquid containing 6 parts by weight and a viscosity of 900 CpS was impregnated with a saturator, and squeezed with a mangle to give a solid content of 85 parts by weight based on 100 parts by weight of the nonwoven fabric.

This resin composition liquid-impregnated sheet was dried for 120 85 seconds while tentering in a dryer, thereby simultaneously foaming the Meklopearl and curing the copolymer by crosslinking. The average diameter of closed cells in the obtained resin foam was 6
5μ, the average diameter of closed cells made of Shirasu balloon is 7
It was 0μ. A reinforced plastic was produced by secondary processing in the same manner as in Example 1 using the above core material. The performance of the core material and reinforced plastic is shown in the table.

Comparative Example 1 - Short fibers made of polyethylene terephthalate (size 1.
．． 5 (1, length 87.511'l) with a basis weight of 60 yen d was impregnated with a resin solution containing 14% by weight of polyacrylonitrile and 6% by weight of Micropearl to form polyacrylonitrile Y42J. An impregnated non-woven fabric with a solid content of 18 micro pearls was produced, and this impregnated non-woven fabric was heated to a maximum temperature of 111 mm to obtain a core material with an average diameter of 80 μm of closed cells. Processed to produce reinforced plastic.

Comparative Example 2.3 In Example 1, the basis weight of the nonwoven fabric, the resin composition liquid,
By changing the component ratio, impregnation amount, heating conditions, etc., a core material with a porosity smaller than the set value of the present invention (Comparative Example 2) and a core material with a porosity larger than the set value of the present invention (Comparative Example 8) were prepared. )° was produced, and this core material was subjected to secondary processing in the same manner as in Example 1 to produce a reinforced plastic.

Comparative Example 4 Example 1 except that a nonwoven fabric with a basis weight of 80% formed from short fibers made of polyethylene terephthalate (thickness 1.5 d, length 87.51 fjf) was used instead of the filament yarn in Example 1. The core material and reinforced plastic were manufactured using the same processing conditions.

The physical properties of the core material and reinforced plastic of each of the above Examples and Comparative Examples are shown in the table below.

Among the physical properties listed above, the thickness is JIS-6828. The specific gravity is 6911 for the bending elastic modulus and bending strength q, 118-, and 6728 for the tensile elevation force #'i and 'JTs-. Tear strength and interlayer peel strength are values measured in accordance with JTS-6772.

The closed cell amount is a value calculated using the following formula.

□)] However, C is the porosity (%), 8 is the basis weight type of the nonwoven fabric, 1I)
n), BII-1 impregnated solid content basis weight (K), y is the thickness of the core material (Wyi), Da is the specific gravity of the hexagonal fiber, and Db is the average specific gravity of the impregnated solid content.

Compression elastic recovery company, vertical IQcN, horizontal 10cIII,
100 core material samples with a thickness of &2.5111 were stacked and left at room temperature for one week, and then the sample from the sliding part was taken out and the thickness measured after being left for one hour.
% or more, good for 95-80%, 80%
Those with a score of less than % were classified as poor.

Molding processability is determined by the fact that when core material is used to manufacture reinforced plastic materials, core material fibers, impregnating agents, etc. fall off.1. Items that are not handled properly are rated as ``not acceptable,'' items with only a small amount of fiber or impregnating agent falling off are rated 1, and items that have not fallen off at all are rated ``
It was rated as "good".

Suitability for cutting reinforced plastic is vertical l0cII1
1 A reinforced plastic plate measuring 10cm wide and 51m thick was cut vertically and horizontally into 23 lengths by sawing.
Cut the parts and mark with ○ if there are no cracks when cutting.
Those with slight cracks are marked with Δ, and those with large cracks are marked with X. The suitability for nail driving work was determined by setting the swing angle of the arm of a nail driving tester (arm length 60 cm, IR 1 load 20 kO) at 60 degrees, and dropping a nail (length 40 mm, needle diameter #18) onto a reinforced plastic plate by gravity. Those with no cracks during shaking and nailing were marked with an ○ mark, those with slight cracks with a △ mark, and those with large cracks with an X mark. For suitability for thread cutting work, use an automatic screw nailer to screw a screw nail (length 4011, flathead type) into a l-plastic plate, and mark with an ○ if no cracks occur when screwing.

Those with slight cracks are marked with △, and those with large cracks are marked with X.

As seen in the table above, the core materials of Examples 1% and 2 have better compressive elastic recovery properties, higher tensile strength, tear strength, and interlayer peeling strength than the comparative examples, and have good moldability.
Reinforced plastics are also suitable for cutting, nailing, and threading.

On the other hand, in Comparative Example 1ift, which is based on the example described in the specification of British Patent No. 1,427,647, the tensile strength, -tear degree, and delamination strength of the core material are small, and the specific gravity of the reinforced plastic is small. is large, the bending performance is low, and various aptitudes are poor. Moreover, in Comparative Example 8, which has a large porosity, the core material has particularly low strong physical properties and the specific gravity of the 1-reinforced plastic is large, and its workability is poor.

[Brief explanation of the drawing]

The drawing is a schematic cross-sectional view of the core material of the present invention. 1: filament yarn, 2: intertwined portion, 8: thermosetting resin foam, 4: closed cell, 5: void. Procedural Amendment (Second) July 1981 281 1. Indication of the case Patent Application No. 46010 of 1988 2. Name of the invention Core material for reinforced plastics 3. Person making the amendment. Relationship to the case Patent applicant Location 1754 Tarui, Sennan City, Osaka Name Toyo Cross Co., Ltd. (one person) 7. Contents of amendment (1) Specification cylinder page 4 line 5 “S1 poor bending properties Also, the aptitude for nailing work is
Corrected to "aptitude for nail driving work". Itl Specification No. 5 Bamboo 5 This gap 5 was corrected. (3) On page 9 of the specification, lines 1 and 2, "Polyurethane" was corrected to "Rigid polyurethane foam." (4) Mei M, page 11, line 21, ``Rigidity (X10kg・fl') J has been corrected to ``Rigidity (X10'phantom'' 11m1) J.

Claims (1)

[Scope of Claims] [1] It is characterized in that the filament yarn of a nonwoven fabric formed from filament yarn and the intertwined portion thereof are co-formed by being covered with a thermosetting resin foam that can contain closed cells. Core material for reinforced plastics. [2] The thermosetting resin according to claim 1, wherein the thermosetting resin is a polyvinyl acetate self-ethylene copolymer, or a mixture of the copolymer and a polyvinyl acetate/ethylene/acrylic terpolymer. Core material for reinforced bus and stick. [8] The core material for reinforced plastics according to claim 1 or 2, wherein the closed cells contained in the thermosetting resin foam have an average diameter of 45 to 135 μm. [4] The core for reinforced plastics according to any one of claims 1 to 3, wherein the thermosetting resin foam contains inorganic hollow spheres with an average particle diameter of 6°0 to 8°μ. Material. [5] The core material for reinforced plastics according to any one of claims 1 to 4, wherein the filament threads constituting the nonwoven fabric are molded from polyethylene terephthalate or nylon synthetic resin.