JPH0467944A - Synthetic resin structure material - Google Patents

Abstract

PURPOSE:To manufacture a synthetic resin structure material, light and of superior heat insulation properties and large strength by bringing uncured thermosetting resin containing fiber and a foaming agent into contact with at least one face of a foamed body of thermoplastic polyester family resin, foaming, curing and integrating the thermosetting resin. CONSTITUTION:In order to foam thermosetting resin, a foaming agent is added to the resin in the uncured state, and the resin is foamed and cured. The uncured thermosetting resin containing fiber and a foaming agent can be prepared easily by mixing the fiber and the foaming agent with the resin. The thermosetting resin containing the fiber and the foaming agent is brought into contact with a thermoplastic polyester resin (PAT) foamed body, and then a space where the resin can be foamed is formed on a contact face of the PAT foamed body and the thermosetting resin the vertical direction, and the resin can be prepared by just heating, and it is not necessary to use a specified adhesive on the foamed body. Thus a structure integrating the foamed resin containing fiber with the PAT foamed body can be manufactured easily and securely.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a synthetic resin structural material that is lightweight, has excellent heat insulation properties, and has high strength.

(Prior Art) Since synthetic resins are lightweight and resistant to corrosion, attempts have been made since ancient times to use them as structural materials. However, synthetic resins generally have the disadvantage of poor strength.

In order to compensate for this, glass fibers or carbon fibers have been mixed into synthetic resins to produce fiber-reinforced resins. Although fiber-reinforced resins are certainly rich in strength and rigidity, on the other hand, because they contain glass and carbon, they have lost their advantage of being lightweight.

In order to improve this, JP-A-1-156051 proposes using a synthetic resin foam as a base material and providing fiber-reinforced resorcinol resin 1 on one side or screen of the foam. . However, the use of polystyrene foam or flexible polyurethane foam as the synthetic resin foam was only considered. However, these foams are originally soft, or even if they are hard, they soften at 100°C, and the resin layer of resorcinol resins has to be heated to 100°C or higher while being pressurized. Therefore, in this proposal, it is not possible to adhere the fiber reinforcing layer to the foam while maintaining its original shape. Therefore, with this proposal, it was not possible to obtain a strong and lightweight synthetic resin structural material. Therefore, there was a demand for a further improved structural material.

(Problem M to be Solved by the Invention) The present invention has been made in an attempt to provide a synthetic resin structural material that is lightweight, has excellent heat insulation properties, and has high strength.

(Means for Solving the Problem) The inventor has discovered that when the resin constituting the foam is polystyrene or soft polyurethane, heating to cure the resorcinol resin causes the foam to deform and return to its original state. However, if thermoplastic polyester resin is used as the resin constituting the foam, the foam will not deform even if heated to temperatures that would cure resorcinol resin or other thermosetting resins. I found out that there is no.

Here, the thermoplastic polyester resin (hereinafter referred to as PAT) is a high molecular weight chain polyester made by causing a condensation reaction between an aromatic dicarboxylic acid and a dihydric alcohol. A typical example is polyethylene terephthalate, which is produced by the condensation of terephthalic acid and ethylene glycol.

In addition, the inventor discovered that when an uncured thermosetting resin, not only resorcinol resins, but a wide variety of thermosetting resins is brought into contact with the surface of a FAT foam and the thermosetting resin is heated and cured, the thermosetting resin is cured. It has been found that the thermosetting resin strongly adheres to the FAT foam by blending in with the irregularities caused by the air bubbles on the surface of the foam. Furthermore, the inventor discovered that by adding reinforcing fibers such as glass fibers to the thermosetting resin, the resulting molded product is reinforced by the fibers, resulting in a strong molded product. I found out. Based on this knowledge, the inventor previously proposed a structural material in which a fiber-reinforced thermosetting resin was integrally provided on one side of a thermoplastic polyester resin foam (Patent Application No. 1999). -344250).

However, in this proposal, foaming a hardening resin containing fibers would create a layer that is lightweight and has excellent heat insulation properties.
Moreover, it has been found that a structural material made of synthetic resin with high strength can be obtained. This invention was made based on such knowledge.

(Summary of the Invention) The present invention provides an integrated synthesis by bringing an uncured thermosetting resin containing fibers and a foaming agent into contact with at least one surface of a FAT foam, foaming and curing the thermosetting resin. This invention relates to resin structural materials.

As mentioned above, FAT used in this invention is a high molecular weight chain polyester made from an aromatic dicarboxylic acid and a dihydric alcohol. In addition to terephthalic acid, examples of aromatic dicarboxylic compounds include isophthalic acid, 2.
6-naphthalene dicarboxylic acid, diphenyl ether dicarboxylic acid, diphenylsulfone dicarboxylic acid, and diphenoxy dicarboxylic acid can be used. In addition to ethylene glycol, examples of dialcohols include trimethylene glycol, tetramethylene glycol, neobenzene gelicol, hexamethylene glycol, cyclohexane dimethylol, tricyclodecane dimethylol, 2.2-bis(4 -β-hydroxyethoxyphenyl)propane, 4,4'-bis(β-hydroxyethoxy)diphenylsulfone, and diethylene glycol can be used. Such FAT is commercially available.

In this invention, commercially available FAT can be used.

FAT is said to be a resin that is difficult to foam.

The reason is that FAT is a crystalline resin, and when it is heated, it rapidly softens and becomes a liquid with low viscosity. That is, FAT has a narrow temperature range in which it exhibits a viscosity suitable for foaming, so it is difficult to maintain the temperature at an appropriate temperature for foaming, and if the viscosity becomes low, the gas that acts as a foaming agent will quickly dissipate. It is for this reason that FAT foam is not widely known in general.

However, the difficulty in foaming has been gradually resolved through subsequent improvements. For example, the difficulty in foaming is gradually being overcome by mixing a jepoxy compound with FAT or adding a compound of a metal belonging to Group 1a or Group 11a of the periodic table. Foaming is also facilitated by adding acid dianhydrides such as pyromellitic anhydride, epoxy compounds such as diglycidyl terephthalate, and sodium carbonate to FAT to improve the melting properties of FAT. be.

The simplest method for producing FAT foam is to extrude and foam FAT. To do this, FAT is placed in an extruder, the FAT is heated and melted, a foaming agent is press-fitted into the molten FAT, a die with a slit-shaped extrusion hole is attached to the tip of the extruder, and the FAT is heated and melted through the extrusion hole. Just push it out into the atmosphere.

If the extrusion hole is in the form of a slit, FAT will be extruded in the form of a sheet, and if foamed successfully, the foam will be several times larger.

When intended as a structural material, FAT is usually not required to be expanded to a very large extent. Therefore, a sheet that has been expanded to several times its original size as described above can be used satisfactorily. However, this does not preclude the use of large foams.

Various foaming agents can be used.

Broadly speaking, these include solid compounds that decompose to generate gas at temperatures above the softening point of FAT, liquids or gases that vaporize within PAT when heated, and inert gases that can be dissolved in FAT under pressure. Either can be used. The solid compounds mentioned above are, for example, azodicarbonamide, dinitrone pentamethylenetetramine, hydrazocarbonamide, sodium bicarbonate, and the like. The above-mentioned vaporized liquids or gases include, for example, saturated aliphatic hydrocarbons such as hexane, pentane, and butane, alicyclic hydrocarbons such as cyclohexane, aromatic hydrocarbons such as benzene and xylene, and methylene chloride. , halogenated hydrocarbons such as Freon®. Examples of the inert gas include carbon dioxide and nitrogen. In addition, as the blowing agent, a high molecular weight chain aromatic polycarbonate can also be used, as taught in Japanese Patent Application Laid-Open No. 59-135237.

Various thermosetting resins can be used. For example, unsaturated polyester resin, epoxy resin,
Phenolic resins can be used. All of these resins are used in an uncured state, but they may be in either powder or liquid form.

The unsaturated polyester resin is a thermosetting resin in which a vinyl monomer is dissolved in a resin (base resin) obtained by a condensation reaction of unsaturated and saturated dicarboxylic acids and dihydric alcohols. The main chain of the base resin contains an unsaturated group, which causes a copolymerization reaction with the vinyl monomer.1. to crosslink and harden. Maleic anhydride and phthalic anhydride are often used as the dicarboxylic acid, dihydric alcohols such as ethylene glycol and propylene glycol are used, and styrene is used as the vinyl monomer. The uncured resin can be obtained as a powder or a low viscosity liquid.

When unsaturated polyester resin is heated by adding an organic peroxide such as benzoyl peroxide, it hardens to produce a hard resin. At this time, if a curing accelerator such as dimethylaniline or cobalt naphthenate is added, curing occurs without the need for heating.

Moreover, this resin forms a layer even without pressurization.

Epoxy resin is a resin having two or more epoxy groups in its molecule. As this resin, polyamides such as pisphenol A polyamide, cycloaliphatic polyamide, and dibutadialiphatic polyamide can be used.

The bisphenol A type is the most commonly used. It is a resin represented by the general formula. Here, n is an integer from 0 to 12. Depending on the number of n, there are various stages from liquid to solid. This is the uncured epoxy resin.

When a hardening agent is added to the uncured epoxy resin, it hardens to produce a hard resin. If an aliphatic diamine, aromatic diamine, aromatic acid anhydride, or aliphatic polyamine is added as a curing agent, it can be cured at room temperature without heating; Heat and harden. Curing can be carried out by applying pressure, but it can also be carried out under normal pressure without applying pressure.

Phenolic resin is a resin made by the reaction of phenol and formaldehyde. Two types of resins with different chemical structures can be obtained depending on the catalyst used.

Resins obtained using alkali as catalysts are called resols.
The resin obtained using acid as a catalyst is called Novolank to distinguish it. The resol initially appears in a liquid state, but when it is further heated, it becomes solid. Novolank is a brittle solid, but when hexamethylenetetramine is added as a curing agent and further heated, it hardens to form a hard resin.

In this invention, fibers are used to reinforce the thermosetting resin as described above. As the fibers, glass fibers, carbon fibers, aromatic polyamide fibers, metal fibers, potassium titanate fibers, silicon carbide fibers, etc. can be used.

The thickness of the fibers is said to be several microns to several tens of microns,
Various fiber lengths can be used as required. The fiber may be in the form of a single fiber, or may be in any form such as yarn, strand, roving, chopped strand, mat, or cloth.

In addition, in this invention, in order to foam the thermosetting resin, when the resin is in an uncured state, a foaming agent is added to it, and the resin is foamed and hardened. Various foaming agents are used. can do. Broadly divided into solid compounds that decompose and generate gas at temperatures above the resin's curing temperature, and liquids and gases that dissolve in the resin at temperatures below the resin's curing temperature and vaporize within the resin when the temperature rises above the resin's curing temperature. can be used. The above solid compound may be, for example, 2
．． These include 2'-azoisobutyronitrile, diazuminohensen, and terephthalazide. Further, the liquid or gas to be vaporized is, for example, petroleum ether or acetone.

An uncured thermosetting resin containing fibers and a blowing agent can be easily prepared by mixing the fibers and blowing agent with a resin. When using an unsaturated polyester resin as the curable resin, a mixture obtained by impregnating a foaming agent into a compound called a sheet molding compound, generally abbreviated as SMC, can be used as is.

In the structural material according to the present invention, a thermosetting resin containing fibers and a blowing agent is brought into contact with a FAT foam, and then the fibers and the thermosetting resin are brought into contact with each other in a direction perpendicular to the contact surface between the FAT foam and the thermosetting resin. This can be created simply by providing space for the resin to foam and heating the resin. There is no need to use special adhesives on the foam. However, if pressure is required to adjust the shape when curing the thermosetting resin,
Put it in a press and apply pressure. However, since FAT foam does not normally soften at temperatures up to 200° C., it does not deform when heated to harden the thermosetting resin. Further, since the FAT foam hardly deforms even when a slight pressure is applied, it hardly deforms even when pressurized when the resin is cured. Even if strongly pressurized, the FAT foam only undergoes elastic deformation and does not lose its foam structure. In this way, a structural material in which the fiber-containing foamed resin and the FAT foam are integrated can be easily and reliably produced.

The fiber-containing foamed resin may be attached to only one side of the FAT foam, but it may also be attached to the screen, with the fiber-containing foamed resin sandwiching the FAT foam in a sandwich structure. It's okay.

(Effects of the Invention) According to this invention, since FAT is used as the foam material, the thermosetting resin is foamed on the surface of PAT because it has heat resistance that does not soften up to 200°C. Even if the foam is cured at the same time, the foam does not lose its foam structure, and therefore a thermosetting resin layer can be provided directly on the foam. Moreover, in this case, since the surface of the foam has irregularities due to air bubbles, the thermosetting resin strongly adheres to the foam, making it difficult to peel off the resulting product. Furthermore, since the thermosetting resin contains fibers, it is reinforced with fibers and has sufficient mechanical strength. Moreover, since no special adhesive is required to make it, it is easy to manufacture. In addition, the thermosetting resin and FAT that make up the product are made from foam, making them lighter in weight, with excellent heat insulating properties, and even more PA
Since the T-foam, the fiber base, and the thermosetting resin all have sufficient heat resistance and mechanical strength, the entire product is lightweight, has good heat insulation properties, and is high in strength. Therefore, this product is suitable for use as a structural material, and is suitable for use in automobiles,
Suitable for use as a structural material for aircraft, ships, etc.

(Example) Hereinafter, the reasons why the structural material according to the present invention is superior will be specifically explained with reference to Examples and Comparative Examples. In the following, parts simply mean parts by weight.

Example 1 (Structure of FAT foam) As FAT, polyethylene terephthalate pellet (manufactured by Kijinsha, TR8580) having an intrinsic viscosity of 0.81 was used.
Using 100 parts, it was heated at a dew point of -20'C and a temperature of 160°C.
After drying with hot air at °C for 5 hours, 0.33 parts of pyromellitic anhydride, 0.1 part of sodium carbonate (both are viscosity modifiers for FAT), and 0.6 parts of talc powder (with air bubbles) were added to this mixture. Adjustment agent) was added, and the mixture was placed in a tumbler and mixed well, and then placed in an extruder.

The extruder had a cylinder temperature of 274-287'C and a die temperature of 277'C. Further, from the middle of the pulling process, butane was injected as a blowing agent at a rate of about 1.0 part.

A nozzle with an annular slit is attached to the tip of the extruder, and FAT containing butane is extruded into a cylindrical shape through the annular slit, and the FAT is foamed as it advances over a cylindrical mandrel. Made a sort. This was then cut open to form a flat sort and wound up into a roll. The obtained foamed sort had a density of 0.2 g/cube and a thickness of 30 mm.

From this, cut out a square sheet with a side of 150m,
This was made into a FAT foam sheet.

(Thermosetting resin containing fibers and foaming agent) Glass fiber cloak with a weight per lrf (hereinafter referred to as basis weight) of 3003 (manufactured by Fuji Fiberglass Co., Ltd., FE
Phenol resin (manufactured by Asahi Yokuzai Co., Ltd., pp-0015, viscosity 5100CP)
/25°C), 30g of curing agent (manufactured by the same company, CA-64)
5) 5g and foaming agent (manufactured by the same company, AA-30) 3.6
The mixture with g was uniformly impregnated, and this was made into an uncured thermosetting resin sheet containing fibers and a foaming agent. I made two sheets like this.

(Manufacture of structural material) A FAT foam sheet was sandwiched between the uncured thermosetting resin sheets containing the above-mentioned fibers and a foaming agent, and this stack was placed in a mold. The formwork has a thickness of 5ao and a side of 18
In a 0 mm square metal plate, one side is 1 at the center.
It is a frame-like item made by punching out 50 squares.
It was a rectangular frame with a width of 15 mm. The stacked material placed in the formwork left space for expansion in the thickness direction of the sheet. Place the mold containing the stacked materials into a press and heat to 90°C while applying a pressure of 40kg/c-d.
A structural material was obtained by heating for 20 minutes.

The obtained structural material has a thickness of 5- and a density of 0.75 g/c.
It was d. JIS K 7203 for bending strength of structural materials
When measured according to
The amount of deflection was 12.4 mm. Also, the elastic modulus is 1
It was 9400 kg, f/cffl. Although an attempt was made to peel off the phenol resin layer and FAT at the interface, the layer could not be peeled off easily. As a result, this structural material can be used for automobiles,
It was recognized that it can be used satisfactorily as a structural material for aircraft and ships.

Comparative Example 1 A structural material was produced in exactly the same manner as in Example 1, except that the use of the blowing agent mixed with the phenolic resin was stopped.

The obtained structural material has a thickness of 5-, a density of Q, and 75 g/
It was an. The structural material has a bending strength of 254 f/c-
j, deflection amount is 6.93mm, elastic modulus is 22800kg
-f/cJ. As a result, although it could be used as a structural material, it was less flexible than that of Example 1.

Example 2 This example differs from Example 1 in that the blending ratios of fiber and blowing agent-containing thermosetting resin are changed, but the FAT foam is the same as in Example 1, and the FAT foam and thermosetting resin are the same as in Example 1. The bonding conditions with the synthetic resin sheet were changed.

To be more specific, the phenolic resin (PF-
0015) 19g and curing agent (CA-645) 2.8g
The glass fiber mantle (FEM-300-04) used in Example 1 was impregnated with a mixture of the above and the blowing agent (AA-30) Ig to form an uncured thermosetting resin sheet. I made two. The same FAT foam used in Example 1 was sandwiched between these sheets, and a press pressure of 35 kg was applied.
/ci for 30 minutes at 80°C to obtain a structural material.

The obtained structural material had a thickness of 51 m [l and a density of 0.5
It was 9g/cU. The bending raw load is 21.2kg-
f, bending strength is 302kg-f/ci, and deflection is 1
The elastic modulus was 14900+lf/c.

Comparative Example 2 A structural material was produced in exactly the same manner as in Example 2, except that the use of the blowing agent mixed with the phenolic resin was stopped.

The obtained structural material has a thickness of 5 mm and a density of 0.59
g/cIl! Met. The bending raw load is 15.3μ
・f, bending strength is 222 kg-f/cffl, deflection is 7.64 mm, elastic modulus is 21400 kg-f/cffl
There was one.

Example 3 (Structure of FAT foam) The foam sheet obtained in Example 1 (density 0.2 g/cd,
Five square sheets with a side of 250 mm were cut from a sheet with a thickness of 30 mm. Three of these sheets are stacked one on top of the other, and between each sheet there is a square with a side of 250 mm and a thickness of 50 mm.
μ polyester hot melt film (PS-28
10: Put the stacked product sandwiching the (manufactured by Daicel Chemical Co., Ltd.) into a press, and while applying a pressure of 0.2 kg/ci,
A primary FAT laminate was obtained by heating at 180°C for 2 minutes. Furthermore, the remaining two sheets are stacked on both ends of this primary FAT laminate, and between each structural member and sheet,
As before, it is a square with 250 marks on one side and a thickness of 50μ.
polyester hot melt film (PS-281
0: manufactured by Daicel Chemical Co., Ltd.) was placed in a press, and while applying a pressure of 0.2 kg/cn,
A secondary FAT laminate was obtained by heating at °C for 2 minutes.

The reason why the FAT sheets were laminated twice is because the FAT sheet itself is a heat insulator, and if too many layers are stacked, the inner layers will not adhere.

(Thermosetting resin containing fiber and foaming agent) Is the basis weight 300g/rT? 250 of glass fiber mat (manufactured by Fuji Fiberglass Co., Ltd., FEM-300-04)
Phenolic resin (manufactured by Asahi Yukizai Co., Ltd., PF-00)
15, viscosity 5100 cp/25°c), 29 g of a hardening agent (manufactured by the same company, CA-645), and 12 g of a blowing agent (manufactured by the same company, AA-30) was uniformly impregnated into the fiber. and an uncured thermosetting resin throat containing a foaming agent. I made two sheets like this.

(Manufacture of structural material) A FAT foam sheet was sandwiched between the uncured thermosetting resin sheets containing the above-mentioned fibers and a foaming agent, and this stack was placed in a mold. The formwork is a frame-like piece made by punching out a square with a side of 250 aan in the center of a square metal plate with a thickness of 2811 II11 and a side of 280 aan, forming a square frame with a width of 15 aaan. It was something.

The stacks placed in the formwork left space for expansion in the thickness direction of the sort. The mold containing the stacked material was placed in a press and heated at 80°C for 30 minutes while applying a pressure of 45 kg/cj to obtain a structural material.

The obtained structural material has a thickness of 28 mm and a density of 0.41 mm.
g/ci. Its thermal conductivity is 0.0 at 20°C.
It was 0339Kcal/m-hr・'c.

Comparative example 3 In this comparative example, it was decided not to use FAT foam.

(The fibers and the foam side stand are thermosetting resin) 25 pieces of glass fiber mat (manufactured by Fuji Fiberglass Co., Ltd., FEmon-300-04) with a basis weight of 300 g/rrr
0 = Square, phenolic resin (manufactured by Asahi Yukizai Co., Ltd., PFo0
15. Uniformly impregnated with a mixture of 330 g of viscosity 5100 cp/25 ° C), 50 g of a curing agent (manufactured by the same company, CA-645), and 17.5 g of a blowing agent (manufactured by the same company, AA-30), This was made into an uncured thermosetting resin sheet containing fibers and a foaming agent. I made two sheets like this.

(Manufacture of structural material) Two uncured thermosetting resin sheets containing the above-mentioned fibers and a foaming agent were stacked on top of each other and placed in a mold.

The formwork is the same as that used in Example 3.

The stacked material placed in the formwork left space for expansion in the thickness direction of the sheet. The mold containing the stacked material was placed in a press and heated at 80° C. for 30 minutes while applying a pressure of 45 kg/cm to obtain a structural material.

The obtained structural material has a thickness of 28= and a density of 0.42 g.
/ad. Its thermal conductivity is 0.04 at 20°C
It was 94Kcal/va-hr・'C.

Claims (1)

[Claims] A synthetic resin structure in which an uncured thermosetting resin containing fibers and a blowing agent is brought into contact with at least one surface of a thermoplastic polyester resin foam, and the thermosetting resin is foamed and cured to form an integrated structure. Material.