JP2979343B2 - A molding substrate, a method for producing the same, and a molded article using the molding substrate. - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] A molding base suitable for use as an automotive ceiling material which is lightweight, has excellent moldability, heat insulation properties and sound absorption properties, and furthermore has excellent bending elastic strength and dimensional stability at high temperatures. It is about materials.

[Conventional technology]

As a molded ceiling material for automobiles, cardboard, various thermoplastic resin foams, and felt-like sheets obtained by applying a thermosetting resin such as a phenol resin are used.

Corrugated cardboard is lightweight and inexpensive, but poor in formability due to low elongation.

Particularly, deep drawing is difficult. For this reason, thermoplastic resin foams have come to be used, and are excellent in lightness and moldability, but are inferior in dimensional stability at high temperature and bending elastic strength at high temperature due to thermoplasticity.

In order to improve the performance at high temperature, phenolic resin of novolak type is sprayed on fiber sheet such as felt instead of thermoplastic resin, or phenol resin of solution type is impregnated into fiber sheet and heat treated to improve dimensional stability at high temperature. The flexural elasticity is improved, but there is a drawback that the degree of impregnation into the fiber sheet is small due to the powder and the weight is increased to obtain the required strength.

[Problems to be solved by the invention]

It solves the above-mentioned conventional disadvantages, is lightweight, has high strength, is excellent in formability, and is excellent in bending elastic strength and dimensional stability at high temperatures.

It is an object of the present invention to provide a molding base particularly suitable for an automobile molding ceiling.

[Means for solving the problem]

The gist of the present invention is to obtain a flexible sheet obtained by impregnating a web obtained by subjecting a fiber assembly to a needle punching treatment with a foamable thermosetting resin liquid and heat-treating at a low temperature.

Laminate an inorganic fiber chop on top of it, apply a thermosetting resin liquid as necessary, provide low-temperature heat treatment in a heating furnace to provide a substrate for temporary fixing molding, and form the fiber by foaming and simultaneous molding with a press molding machine. An object of the present invention is to obtain a light-weight and very rigid molding base material in which a web, an inorganic fiber chop, and a foaming thermosetting resin are integrated, and which are very rigid, and particularly excellent in bending elastic strength and dimensional stability at high temperatures.

The fiber of the web serving as the base of the molding substrate of the present invention is not particularly limited, and is a binderless material treated by a needle punch method or a hydroentanglement method with a web composed of organic fibers or organic fibers and inorganic fibers. What is necessary is just to add the elongation at the time of molding with the fiber aggregate.

The foamable thermosetting resin is most suitable as the resin impregnating the web.

Conventionally, foamed phenolic resin on powder (Tokuhei 1-2719)
2, there is a resin felt using JP-A 64-72836), but the degree of impregnation into the web is small and the hardness increase is small.
Therefore, a liquid resin is used in order to improve the degree of impregnation into the web by emulsifying or forming the foamed phenolic resin into a solution and to improve the adhesiveness between the fiber resin and the fibers. The foamable thermosetting resin includes a phenol resin, a polyurethane resin, and an unsaturated polyester resin.

As the inorganic fiber chop, a glass fiber having a fiber diameter of 3 μm to 20 μm and a fiber length of 3 mm to 100 mm is preferable, and weighs 50 to 200 g.
/ m ² to be laminated on one or both sides of the phenol-impregnated web, apply phenolic resin as necessary to improve the adhesion with the foamed phenolic resin, and cure at 80 to 100 ° C.
Heat treatment at a temperature lower than the foaming temperature.

A laminated sheet impregnated with a foaming thermosetting resin (phenolic resin) is introduced into a press molding machine, and is heated at 180 ° C for about 3 minutes for foaming and curing in the press molding machine, and cured at the same time as foaming. Obtain molded articles. During foaming, the resin impregnation of the glass chop mat progresses due to the increase in capacity, the adhesion between the phenolic resin and the glass chop mat is improved, and a synergistic effect with the hardness of the resin itself is obtained to increase the hardness.

The molding substrate of the present invention uses a web and an inorganic fiber chop mat that have undergone a needle punching process as the substrate, and the foamable thermosetting resin impregnated therein is heat-treated at a curing temperature or lower. Since it is in an uncured state, it is a base material having good moldability that easily fits into a mold having a complicated shape.

Further, for example, by laminating a thermoplastic fiber non-woven fabric made of polyester fiber on the surface of the inorganic fiber chop mat, when molding using the molding base, the releasability of the base from the mold is improved. Can be done.

(Effects)

Generally, a foamable thermosetting resin cannot be subjected to secondary molding due to thermal curing when the foaming and curing steps are completed. If not cured, it does not contribute to imparting hardness.

One of the features of the molding substrate of the present invention is that simultaneous foaming and curing in a press molding machine is possible, so by foaming and simultaneous molding in the press molding machine, the phenol resin penetrates into the fiber layer at the time of foaming, and the fiber and This contributes to an increase in hardness as well as an increase in hardness, and a step of curing and molding at the same time as foaming prevents overfoaming and the like, thereby obtaining a stable molded product.

The molded article using the molding base material of the present invention has a foaming structure and therefore uses a thermosetting resin, but has favorable properties as an automobile ceiling base material such as cushioning properties, light weight properties, heat insulation properties, and sound absorption properties. have.

〔Example〕

(Example 1) A solution prepared by dissolving 100 parts of a novolak type foamed phenol resin in 200 parts of an ascent / methanol (50/50) solvent is prepared as an impregnation liquid.

On the other hand, 35 parts by weight of polypropylene bristles were mixed with 65 parts by weight of polyester bristles to form a web, and this was needle-punched (32-felt needle, punch density 90 points / c
m ² , needle penetration length: 11mm), thickness about 2mm, weight 200g
/ m ² needle punch felt was obtained.

After immersing the needle punch felt in the impregnating liquid, the solvent was evaporated at 70 ° C. to obtain a foamed phenol-impregnated mat having a weight of 500 g / m ² and a thickness of about 2 mm.

Next, a chopped strand mat (100 g / m ^2, made of glass fiber with a length of 50 mm and a diameter of 13 μm) is laminated on the obtained mat-shaped screen, and sprayed with a water-soluble resol type phenol on both sides of the chopped strand mat. The resin was applied in an amount of 50 g / m ² each to obtain a molding substrate.

This molding substrate is subjected to simultaneous foaming and curing for 90 seconds under the conditions of a mold temperature of 230 ° C., a pressure of 6 kg / cm ² , and a clearance of 3 mm,
A molded product was obtained. The obtained molded article was lightweight, and excellent in heat insulation and sound absorption.

(Example 2) obtained in Example 1, foaming phenol resin-impregnated mat-like material on both surfaces laminated chopped strand mat (weight 230 g / m ²⁾ of an aqueous solution in the same manner as followed in Example 1 Weight g / m ² A resol type phenol and a phenol resin were applied to obtain a molding substrate.

The molding base was foamed and cured simultaneously by a hot press to obtain a molded product.

Example 3 On both sides of the foamed phenolic resin-impregnated mat having a weight of 500 g / m ² obtained in Example 1, an unsaturated polyester impregnated with ras prepreg (glass fiber: length 50 mm, diameter 13)
μm, 100 g / m ² , unsaturated polyester 50 g / m ² ), and polyester 3d × 51 mm, 100% weight 3
A nonwoven fabric of 0 g / m ² was laminated to obtain a molding substrate.

This molding substrate was foam-cured simultaneously for 90 seconds under the conditions of a mold temperature of 230 ° C., a pressure of 6 kg / cm ² , and a clearance of 3 mm to obtain a molded product.

From the molded products obtained in Examples 1 to 3, a length of 150 mm and a width of 50 m
m test pieces and span 100m with universal testing machine
m, perform a bending test at a crosshead descent speed of 20 mm / min.
The flexural strength at break and the desorption rate were determined and compared with the measurement results of the comparative examples. As shown in the following table, they were excellent.

(Comparative example 1) Normally, 30 parts by weight of novolak type phenol resin powder was added as a binder to 100 parts by weight of natural fiber and synthetic fiber bristles, and the two were well mixed with a fleece forming machine to form a sheet and weigh 1400 g / m ^2. The resin felt was obtained. This resin felt is heated at a mold temperature of 230 ° C, a pressure of 6 kg / cm ² , and a clearance of 3 m.
Press molding was performed for 60 seconds under the condition of m to obtain a molded product.

Claims (6)

(57) [Claims] An inorganic fiber chop mat is laminated on one or both sides of a sheet in which an expandable thermosetting resin is impregnated into a fiber assembly of a binderless organic fiber or a mixed fiber of an organic fiber and an inorganic fiber. A molding substrate characterized in that: 2. An organic fiber or a mixed fiber of an organic fiber and an inorganic fiber is entangled in a binderless state, and then impregnated with a foaming thermosetting resin to form the foaming thermosetting resin. A method for producing a molding substrate, comprising laminating an inorganic fiber chop mat on one or both sides of a sheet heat-treated at a curing temperature or lower. 3. An inorganic fiber chop mat is laminated on one or both sides of a sheet in which an expandable thermosetting resin is impregnated into a fiber assembly of a binderless material comprising organic fibers or a mixed fiber of organic fibers and inorganic fibers. Molded product obtained by simultaneously molding a base material with foaming. 4. An inorganic fiber chop mat is laminated on one or both sides of a sheet in which a foamable thermosetting resin is impregnated with a binderless fiber assembly comprising organic fibers or a mixed fiber of organic fibers and inorganic fibers. Further, a molding substrate characterized in that a thermoplastic fiber nonwoven fabric is laminated on the surface of the inorganic fiber chop mat. 5. An entanglement treatment of an organic fiber or a mixed fiber of an organic fiber and an inorganic fiber in a binderless state, followed by impregnation with an expandable thermosetting resin, followed by foaming of the expandable thermoset resin. A method for producing a molding substrate, comprising laminating an inorganic fiber chop mat on one or both sides of a sheet heat-treated at a curing temperature or lower, and laminating a thermoplastic fiber nonwoven fabric on the surface of the inorganic fiber chop mat. 6. An inorganic fiber chop mat is laminated on one or both sides of a sheet impregnated with an expandable thermosetting resin on a fiber laminate of a binderless organic fiber or a mixed fiber of an organic fiber and an inorganic fiber, Further, a molded article obtained by simultaneously molding a molding substrate in which a thermoplastic fiber nonwoven fabric is laminated on the surface of the inorganic fiber chop mat and foaming.