JPH03199044A - Synthetic resin structural material - 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 (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 resin is certainly rich in strength and rigidity, it has lost its advantage of being lightweight because it contains glass and carbon.

In order to improve this, JP-A-1-156051 proposes using a synthetic resin foam as a base material and providing a layer of resorcinol resin reinforced with fibers on one or both sides 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 resorcinol resins cannot form a resin layer unless heated to 100°C or higher while pressurizing. Therefore, with 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 structural material made of Hewei resin. Therefore,
There was a demand for further improved structural materials.

(Problems 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. This invention was made based on such knowledge.

(Summary of the Invention) The present invention relates to a synthetic resin structural material made by bringing an uncured thermosetting resin containing fiber into contact with at least one surface of a FAT foam and curing the thermosetting resin.

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, aromatic dicarboxylic acids include isophthalic acid, 2.6
-S7tale dicarboxylic acid, diphenyl ether dicarboxylic acid, diphenylsulfone dicarboxylic acid, and diphenoxy dicarboxylic acid can be used. In addition to ethylene glycol, examples of dihydric alcohols include trimethylene glycol, tetramethylene glycol, neobenzene gelylcol, hexamethylene glycol, cyclohexane dimethylol, tricyclodecane dimethylol, 2.2-bis(4- β-hydroxyethoxyphenyl)prono)1, 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. In other words, FAT has a narrow temperature range in which it exhibits a viscosity suitable for foaming, so it is difficult to maintain the temperature at a suitable temperature for foaming, and when the viscosity becomes low, the gas that acts as a foaming agent quickly dissipates. . 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 r1a 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 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 is extruded in the form of a sheet, and foams relatively well, resulting in several times the foam size.

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, dinitrosopentamethylenetetramine, 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 blowing agents, as taught in Japanese Patent Application Laid-open No. 59-135237,
High molecular weight linear aromatic polycarbonates can also be used.

Various thermosetting resins can be used. For example, unsaturated polyester resin, epoxy resin,
Phenolic resins can be used. All of these resins are in an uncured state and are in 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, and this and the vinyl monomer cause a copolymerization reaction, resulting in crosslinking and curing. Maleic anhydride and phthalic anhydride are often used as dicarboxylic acids, ethylene glycol and propylene glycol are used as dihydric alcohols, and styrene is used as a vinyl monomer. The uncured product of this resin is obtained as a powder or a low viscosity liquid.

When an organic peroxide such as benzoyl peroxide is added to an unsaturated polyester resin and heated, 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. This resin is classified into various types such as bisphenol A type resin, cycloaliphatic type resin, and polybutadiene derived resin, among which bisphenol A type resin is often used. This is a resin represented by the general formula. Here, no
-12 integer. There are various stages from liquid to solid depending on the number of n. This is the uncured epoxy resin.

When a curing agent is added to uncured epoxy resin, it hardens to produce a hard resin. Aliphatic diamine as a curing agent,
Aromatic diamines, aromatic acid anhydrides, aliphatic polyamides, etc. can be used.

When an aliphatic polyamine is added, it can be cured at normal humidity without heating, and when an aromatic diamine or an aromatic acid anhydride is added, it can be cured by heating.

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.
Resins obtained using acids as catalysts are called 7boraks to distinguish them. The resol initially appears in a liquid state, but when it is further heated, it becomes solid. / Borac is a brittle solid, but when it is further heated with hexamethylenetetramine as a curing agent, it hardens to produce a hard resin.

In this invention, fibers are used to reinforce the thermosetting resin. 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 m-fibers is several microns to several tens of microns, and fibers of various 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.

An uncured thermosetting resin containing fibers can be easily prepared by mixing fibers and fat. In the case of using an unsaturated polyester resin as the curable resin, a resin called "Funbound" for sheet molding, generally abbreviated as "SM+O", can be used as is.

The structural material according to the present invention can be produced by simply bringing a fiber-containing thermosetting resin into contact with the FAT foam and then curing the AT resin.

There is no need to use special adhesives on the foam.

However, when heating is required to cure the thermosetting resin, it is heated, and when pressurization is required, it is placed in a press and pressurized. However, FAT foam typically has 2
Since it does not soften at temperatures up to 00°C, it does not deform even when heated to harden the thermosetting resin. Also, F
Since AT foam hardly deforms when a small amount of pressure is applied, it hardly deforms even if pressure is applied 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 resin and the FAT foam are integrated can be easily and reliably produced.

The lIA fiber-containing resin may be applied to only one side of the FAT foam, but it can also be applied to both sides and the fiber-containing resin
n may sandwich the FAT foam therein to form a sandwich structure.

(Effects of the Invention) According to this invention, since PAT is used as the material for the foam, the thermosetting resin is hardened on the surface of the PAT because it has heat resistance that does not soften at 200°C. However, the foam does not lose its foam structure, and therefore a thermosetting resin layer can be applied directly onto the foam. Moreover, in this case, since the foam has irregularities on its surface based on 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 products made in this way are lightweight because they contain FAT foam, and have excellent insulation properties, and both FAT foam and fiber-containing thermosetting resins are The entire product has excellent heat resistance and mechanical strength.
It is lightweight, has excellent insulation properties, and is highly strong. Therefore, this product is suitable for use as a structural material.
Suitable for use as a structural material for automobiles, 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 (Manufacture of PAT foam) As PAT, polyethylene terephthalate pellets (manufactured by Kijinsha, TR8580) with an intrinsic viscosity of 0.81 were used.
0 parts, at a dew point of -20°C and a temperature of 160°C.
After drying with hot air for 5 hours, 0.3 part of pyromellitic anhydride and 0.1 part of sodium carbonate (both F
AT viscosity modifier) and 0.6 part of talc powder (bubble modifier) were added, and the mixture was placed in a tumbler and mixed well, and then placed in an extruder.

The extruder has a cylinder temperature of 274-287°C;
The temperature of the cap was 277°C. Also, about 1.0 part of butane was press-injected as a blowing agent from the middle of the syringe.

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. I made a sheet. This was then cut open to form a flat sheet, which was then wound up into a roll. The obtained foam sheet had a density of 0.262 g/cTA, a thickness of 1.45 mm, and a width of 640 mm.

(Fiber-containing thermosetting resin) SMC (manufactured by Dainippon Ink Chemical Co., Ltd., DICMAT 2454A) was used as the fiber-containing thermosetting resin.

(Manufacture of lumber I) A 200 m++ square FAT foam was sandwiched between the above SMCMC15O+ squares, and this sized material was placed in a formwork. The formwork was made by punching out a square with a side of 200m in a square metal plate with a thickness of 2m and a side of 250m, which was different from a square frame with a width of 25m. Put the above stack together with this mold into a press,
It was heated at 150°C for 5 minutes while applying a pressure of 30 kg/cd. In this way, a structural material was obtained.

The structural material has a thickness of 2.711I11 and a density of 1.17.
g/aj. The thickness was greater than the mold thickness because the FAT foam foamed further when removed from the press.

When the bending strength of the structural material was measured according to JIS K 7203, the bending load was 9.64 kgf and the amount of deflection was 14.6 kgf. Further, when an attempt was made to peel off the SMC and FAT foam at the interface, it did not come off easily, and when the SMC and FAT foam were forcibly peeled off, the FAT foam was destroyed.

Example 2 Weight per rrr (hereinafter referred to as basis weight) is 300g
Glass fiber mat (manufactured by Fuji Fiberglass Co., Ltd., F
EM-300-04) 150 m square and phenolic resin (manufactured by Asahi Yukizai Co., Ltd., PF-0015, viscosity 5300 C
P/25'C) 52g, curing agent (manufactured by the same company, AD-14
) 4 g was placed on both sides of the FAT foam used in Example 1 to create a superposition, which was placed in a mold. As a formwork, the thickness is 51! ! A square metal plate with a side of 180 mm and a square frame of 150 countries on the - side were punched out, and a square frame with a width of 15 mm was used. The above stacked product was placed in a press together with this mold and heated at 80° C. for 30 minutes while applying a pressure of 30 kg/d. In this way, a structural material was obtained.

The structural material has a thickness of 5.8 cm and a density of 0.88 g/c4
Met. When the bending load was measured in the same manner as in Example 1, it was 27.7 kgf and the amount of deflection was 6.9 m.

When this laminate was also attempted to be peeled off at the interface, it could not be peeled off until the PAT foam was destroyed. Adhesion was extremely good.

Comparative Example 1 Instead of the FAT foam used in Example 1,
Example 1 was carried out in exactly the same manner as in Example 1 except that a heat-resistant polystyrene foam having a thickness of 1.85 m was used, and the polystyrene foam did not melt and retain its original shape as a foam.

Comparative Example 2 Instead of the FAT foam used in Example 1,
gSr! Example 1 was carried out in exactly the same manner as in Example 1, except that a polypropylene resin foam with an i-mi of 0.7- was used. Although the polypropylene resin foam was not deformed at all, the adhesion at the interface was poor. It peeled off easily.

Comparative Example 3 Instead of the FAT foam used in Example 2, a
Example 2 was carried out in exactly the same manner as in Example 2, except that a polystyrene foam with a thickness of 1.85 mta was used. Although the polystyrene resin foam did not deform in any way, the adhesiveness at the interface was poor and it easily formed. Peeled off.

Claims (1)

[Claims] A synthetic resin structural material made by bringing an uncured thermosetting resin containing fibers into contact with at least one surface of a thermoplastic polyester resin foam and curing the thermosetting resin.