JP7639436B2 - Resin composition, sheet molding compound, and molded article - Google Patents

Description

The present invention relates to a resin composition, a sheet molding compound, and a molded article.

Sheet molding compound (hereinafter sometimes abbreviated as "SMC") is a sheet-shaped molding material made by impregnating fibers into a paste (compound) made by kneading thermosetting resins, mainly consisting of unsaturated polyester resins and vinyl ester resins, inorganic fillers, thickeners, hardeners, etc., and then maturing it to B stage. Molded products are obtained by heating and pressurizing this SMC. Such molded products have excellent properties such as durability, water resistance, and mechanical strength, and are widely used as housing components such as bathtubs, water tanks, septic tanks, pipe lining materials, electrical parts, vehicle materials, aircraft materials, etc. In particular, vehicle materials and aircraft materials are required to be lightweight, and high flame retardancy is required for parts other than the exterior.

As a method for making molded products lighter, for example, the addition of hollow fillers such as hollow glass beads and glass microballoons has long been known. In addition, as a method for making molded products flame retardant, the addition of aluminum hydroxide or phosphorus- or bromine-based flame retardants is known.

For example, bulk molding compounds (BMC) with a specific gravity of 1.20 have been reported as a way to reduce the weight of molded products (see, for example, Patent Document 1), but there have been no reported examples of sheet molding compounds that are both flame-retardant and have a specific gravity of 1.2. The reason for this is that SMC requires a process in which the compound is impregnated into long glass fibers, so the compound viscosity must be set lower than that of BMC. Thus, in the field of SMC, all methods for reducing weight and making the product flame-retardant have the problem of increasing the compound viscosity, and it has been considered difficult to achieve both weight reduction and flame retardancy at a practical level.

JP 2006-206690 A

The problem that the present invention aims to solve is to provide a resin composition that can produce molded products that have excellent viscosity, flame retardancy, and lightweight properties that are suitable for manufacturing.

The present invention provides a resin composition containing a resin component (A) that contains an unsaturated polyester resin (a1) and styrene (a2), and is characterized in that the resin composition contains 1 to 6 parts by mass of a wetting and dispersing agent (B), 15 to 40 parts by mass of glass balloons (C), and 10 to 30 parts by mass of a flame retardant (D) relative to 100 parts by mass of the resin component (A).

The present invention also provides a sheet molding compound containing the resin composition and reinforcing fibers (F), and a molded article molded from the sheet molding compound.

The resin composition of the present invention can produce molded products with excellent viscosity, flame retardancy, and lightweight properties that are suitable for manufacturing. Therefore, the resin composition of the present invention can be particularly suitably used in applications that require lightweight and flame retardant properties, such as vehicle materials and aircraft materials.

The resin composition of the present invention is a resin composition containing a resin component (A) that contains an unsaturated polyester resin (a1) and styrene (a2), and contains 1 to 6 parts by mass of a wetting and dispersing agent (B), 15 to 40 parts by mass of glass balloons (C), and 10 to 30 parts by mass of a flame retardant (D) relative to 100 parts by mass of the resin component (A).

The resin component (A) contains unsaturated polyester resin (a1) and styrene (a2) as essential components, but may also contain other thermosetting resins (a3) other than the unsaturated polyester resin (a1), other polymerizable unsaturated monomers (a4) other than the styrene (a2), and low-shrinkage agents (a5), etc.

The unsaturated polyester resin (a1) in the resin component (A) has a high viscosity, so it is preferable to dilute it with styrene (a2) before mixing it with other components, and it is preferable to use it as a styrene solution with a non-volatile content of 30 to 80% by mass. The unsaturated polyester resin (a1) can be used alone or in combination of two or more types.

As the wetting and dispersing agent (B), a polymeric wetting and dispersing agent having an acid group is preferable, and specific examples thereof include polymeric wetting and dispersing agents manufactured by BYK Japan KK; BYK-W940, BYK-W972, BYK-W974, BYK-W996, BYK-W9010, BYK-W9011, Disper-BYK110, Disper-BYK111, Disper-BYK180, etc. These wetting and dispersing agents (B) can be used alone or in combination of two or more types.

The glass balloons (C) may be, for example, glass micro hollow sphere powder made of chemically stable insoluble glass, which has a true spherical shape with a particle diameter of about 16 to 65 μm (median diameter) and a true density of about 0.13 to 0.60 g/cm ^3. Here, examples of the glass balloons include glass balloons manufactured by 3M Japan Ltd., such as Glass Bubbles S32HS, Glass Bubbles iM16K, and Glass Bubbles K46, which are commercially available products.

As the flame retardant (D), for example, bromine-based flame retardants; inorganic salts such as antimony trioxide and antimony pentoxide; red phosphorus-based flame retardants; nitrogen-based flame retardants such as melamine cyanurate and melamine polyphosphate; and phenol-based flame retardants such as phenol-based flame retardants can be used. These flame retardants may be used alone or in combination of two or more. Among these, one or more selected from the group consisting of bromine-based flame retardants, antimony trioxide, and red phosphorus-based flame retardants are preferred from the viewpoint of maintaining high levels of flame retardancy, manufacturability, and light weight.

Examples of the brominated flame retardants include brominated aliphatic or alicyclic hydrocarbons such as hexabromocyclododecane, brominated aromatic compounds such as hexabromobenzene, ethylene bis pentabromodiphenyl, decabromodiphenylethane, decabromodiphenyl ether, octabromodiphenyl ether, and 2,3-dibromopropyl pentabromophenyl ether, tetrabromobisphenol A, tetrabromobisphenol A bis(2,3-dibromopropyl ether), tetrabromobisphenol A (2-bromoethyl ether), tetrabromobisphenol A diglycidyl ether, and tetrabromobisphenol A diglycidyl ether. Brominated bisphenols and their derivatives, such as an adduct of trabromobisphenol A diglycidyl ether and tribromophenol, brominated bisphenol derivative oligomers, such as tetrabromobisphenol A polycarbonate oligomers and epoxy oligomers of an adduct of tetrabromobisphenol A diglycidyl ether and brominated bisphenols, brominated aromatic compounds, such as ethylene bistetrabromophthalimide and bis(2,4,6-tribromophenoxy)ethane, brominated acrylic resins, and ethylene bisdibromonorbornane dicarboximide brominated flame retardants, can be used. These flame retardants may be used alone or in combination of two or more.

As the red phosphorus-based flame retardant, for example, red phosphorus or red phosphorus particles whose surfaces are coated with a resin such as a phenolic resin can be used. Among these, red phosphorus particles whose surfaces are coated with a resin are preferred because they are safer and have better dispersibility when mixed with a resin component.

The resin composition of the present invention contains the resin (A), the wetting dispersant (B), the glass balloons (C), and the flame retardant (D) as essential components, but the amount of each is extremely important. Specifically, it is essential to contain 1 to 6 parts by mass of the wetting dispersant (B), 15 to 40 parts by mass of the glass balloons (C), and 10 to 30 parts by mass of the flame retardant (D) relative to 100 parts by mass of the resin component (A) in order to obtain excellent manufacturability, flame retardancy, and light weight, and more preferably, the ranges are 2 to 6 parts by mass of the wetting dispersant (B), 15 to 34 parts by mass of the glass balloons (C), and 10 to 20 parts by mass of the flame retardant (D) relative to 100 parts by mass of the resin component (A). Within these ranges, it is possible to obtain excellent flame retardancy and light weight while suppressing an increase in the viscosity of the compound.

The resin composition of the present invention may contain other additives in addition to the above (A) to (D) as necessary.

Examples of the other additives that can be used include inorganic fillers (E), reinforcing fibers (F), polymerization initiators, thickeners, polymerization inhibitors, curing accelerators, shrinkage reducing agents, release agents, viscosity reducing agents, pigments, antioxidants, plasticizers, flame retardants, antibacterial agents, UV stabilizers, reinforcing materials, and photocuring agents. These compounds may be used alone or in combination of two or more. Among these, when the resin composition of the present invention is used as a sheet molding compound, it is preferable that the composition contains inorganic fillers (E) and reinforcing fibers (F).

Examples of the inorganic filler (E) include calcium carbonate, sodium hydroxide, clay, talc, kaolin, silica, etc. These compounds may be used alone or in combination of two or more.

The amount of the inorganic filler (E) used is preferably in the range of 20 to 80 parts by mass per 100 parts by mass of the resin component (A).

Examples of the reinforcing fiber (F) include glass fiber, carbon fiber, silicon carbide fiber, alumina fiber, boron fiber, metal fiber, and organic fibers such as aramid fiber, vinylon fiber, and tetron fiber. Glass fiber or carbon fiber is preferred because it gives a molded product with higher strength and elasticity. These reinforcing fibers (F) can be used alone or in combination of two or more types.

The length of the reinforcing fibers (F) is preferably in the range of 3 to 60 mm from the viewpoint of the cuttability of the fibers themselves and impregnation with the resin component (A). Reinforcing fibers of different lengths may also be mixed.

The content of the reinforcing fiber (F) in the molding material of the present invention is preferably in the range of 10 to 50% by mass, more preferably in the range of 15 to 35% by mass, since this further improves the mechanical strength of the resulting molded article.

The resin composition of the present invention is useful as a sheet molding compound (SMC). Examples of the method for producing the SMC include a method in which the components (A) to (E) are mixed and dispersed using a mixer such as a normal mixer, intermixer, planetary mixer, roll, kneader, or extruder, the resin composition obtained is applied to a carrier film placed above and below so as to have a uniform thickness, reinforcing fiber (F) is sandwiched between the resin composition on the carrier films placed above and below, and then the whole is passed between impregnation rolls to apply pressure to impregnate the reinforcing fiber (F) with the resin composition, and then wound into a roll or folded in a zigzag shape. Furthermore, it is preferable to carry out aging at a temperature of 25 to 55°C after this. As the carrier film, a polyethylene film, a polypropylene film, a laminate film of polyethylene and polypropylene, polyethylene terephthalate, nylon, etc. can be used.

The molded product of the present invention can be obtained from the SMC, but from the viewpoints of excellent productivity and design versatility, the preferred molding method is hot compression molding of SMC.

The hot compression molding may involve, for example, weighing out a predetermined amount of molding material such as SMC, pouring it into a mold preheated to 80-180°C, clamping the mold with a compression molding machine, imprinting the molding material, and maintaining a molding pressure of 0.1-30 MPa to harden the molding material, and then removing the molded product to obtain the molded product. Specific molding conditions are preferably those in which a mold temperature of 100-160°C is maintained in the mold and a molding pressure of 1-10 MPa is maintained for 1-2 minutes per 1 mm of molded product thickness, and more preferably those in which a mold temperature of 120-160°C is maintained and a molding pressure of 1-10 MPa is maintained for 30-150 seconds per 1 mm of molded product thickness, as this further improves productivity.

As described above, the resin composition of the present invention can produce molded products with excellent viscosity, flame retardancy, and lightweight properties that are suitable for manufacturing. Therefore, the resin composition of the present invention can be particularly suitably used in applications that require lightweight and flame retardant properties, such as vehicle materials and aircraft materials.

The present invention will be explained in more detail below with specific examples.

Example 1 Preparation of Resin Composition (1) 80 parts by mass of an unsaturated polyester resin solution ("Sandoma PS-281" manufactured by DIC Materials Corporation; a mixture of 60% by mass of unsaturated polyester resin and 40% by mass of styrene), 100 parts by mass of a polystyrene resin solution ("Sandoma PS-281" manufactured by DIC Materials Corporation; a mixture of 60% by mass of unsaturated polyester resin and 40% by mass of styrene) and 100 parts by mass of a styrene-based resin solution ("Sandoma PS-281" manufactured by DIC Materials Corporation) were mixed. PS-954"; a mixture of 30% by mass of polystyrene and 70% by mass of styrene), 15 parts by mass of styrene, 5 parts by mass of a polymerization inhibitor ("Parabenzoquinone" manufactured by Seiko Chemical Co., Ltd.), 0.1 parts by mass of a wetting and dispersing agent ("BYK-W9010" manufactured by BYK-Chemie Co., Ltd.), 4 parts by mass of zinc stearate, 70 parts by mass of aluminum hydroxide, 18 parts by mass of glass balloons ("Glass Bubbles S32HS" manufactured by 3M Japan Ltd.), 9 parts by mass of decabromodiphenylethane, 3 parts by mass of antimony trioxide, 1 part by mass of magnesium oxide, and 1.5 parts by mass of a polymerization initiator ("Trigonox 22-70E" manufactured by Kayaku Nouryon Co., Ltd.) were mixed by a dissolver to obtain a resin composition (1).

[Manufacturing of SMC]
The resin composition (1) obtained above was uniformly applied onto two polypropylene carrier films placed above and below, and 70.5 parts by mass of glass fiber ("PB-549" manufactured by Nitto Boseki Co., Ltd.) cut to 25.4 mm was sandwiched between the resin composition on the carrier films placed above and below. The whole was passed between impregnation rolls to apply pressure to impregnate the glass fiber with the resin composition, and then cured at 45°C for 24 hours to obtain SMC (1) with a glass fiber content of 25 mass%.

Example 2 Preparation of Resin Composition (2) and Production of SMC (2) Resin composition (2) was obtained in the same manner as in Example 1, except that the amount of aluminum hydroxide used in Example 1 was changed from 70 parts by mass to 45 parts by mass, the amount of glass balloons used was changed from 18 parts by mass to 20 parts by mass, the amount of decabromodiphenylethane used was changed from 9 parts by mass to 12 parts by mass, and the amount of antimony trioxide used was changed from 3 parts by mass to 4 parts by mass. SMC (2) was obtained in the same manner as in Example 1, except that the amount of glass fiber used was changed from 70.5 parts by mass to 64.2 parts by mass.

Example 3 Preparation of resin composition (3), production of SMC (3) Resin composition (3) was obtained in the same manner as in Example 1, except that in Example 1, the amount of wetting dispersant used was changed from 5 parts by mass to 6 parts by mass, the amount of aluminum hydroxide used was changed from 70 parts by mass to 30 parts by mass, the amount of glass balloons used was changed from 18 parts by mass to 24 parts by mass, the amount of decabromodiphenylethane used was changed from 9 parts by mass to 12 parts by mass, and the amount of antimony trioxide used was changed from 3 parts by mass to 4 parts by mass. SMC (3) was obtained in the same manner as in Example 1, except that the amount of glass fiber used was changed from 70.5 parts by mass to 60.9 parts by mass.

Example 4 Preparation of resin composition (4), production of SMC (4) Resin composition (4) was obtained in the same manner as in Example 1 except that the amount of wetting dispersant used in Example 1 was changed from 5 parts by mass to 6 parts by mass, the amount of aluminum hydroxide used was changed from 70 parts by mass to 30 parts by mass, the amount of glass balloons used was changed from 18 parts by mass to 24 parts by mass, the amount of decabromodiphenylethane used was changed from 9 parts by mass to 16 parts by mass, and the amount of antimony trioxide used was changed from 3 parts by mass to 0 parts by mass. SMC (4) was obtained in the same manner as in Example 1 except that the amount of glass fiber used was changed from 70.5 parts by mass to 60.9 parts by mass.

Example 5 Preparation of resin composition (5), production of SMC (5) In Example 1, the amount of the wetting dispersant used was changed from 5 parts by mass to 6 parts by mass, the amount of aluminum hydroxide used was changed from 70 parts by mass to 30 parts by mass, the amount of glass balloons used was changed from 18 parts by mass to 24 parts by mass, the amount of decabromodiphenylethane used was changed from 9 parts by mass to 0 parts by mass, the amount of antimony trioxide used was changed from 3 parts by mass to 0 parts by mass, and 16 parts by mass of red phosphorus ("Nova Red 120" manufactured by Rin Kagaku Kogyo Co., Ltd.) was newly added. Except for this, a resin composition (5) was obtained in the same manner as in Example 1, and an SMC (5) was obtained in the same manner as in Example 1, except for changing the amount of glass fiber used from 70.5 parts by mass to 60.9 parts by mass.

Example 6 Preparation of Resin Composition (6) and Production of SMC (6) A resin composition (6) was obtained in the same manner as in Example 1, except that in Example 1, the amount of the wetting dispersant used was changed from 5 parts by mass to 6 parts by mass, the amount of aluminum hydroxide used was changed from 70 parts by mass to 30 parts by mass, the amount of glass balloons used was changed from 18 parts by mass to 30 parts by mass, the amount of decabromodiphenylethane used was changed from 9 parts by mass to 12 parts by mass, and the amount of antimony trioxide used was changed from 3 parts by mass to 4 parts by mass. An SMC (6) was obtained in the same manner as in Example 1, except that the amount of glass fiber used was changed from 70.5 parts by mass to 62.9 parts by mass.

Comparative Example 1 Preparation of Resin Composition (R1) and Production of SMC (R1) Resin composition (R1) was obtained in the same manner as in Example 1, except that in Example 1, the amount of wetting dispersant used was changed from 5 parts by mass to 10 parts by mass, the amount of aluminum hydroxide used was changed from 70 parts by mass to 30 parts by mass, the amount of glass balloons used was changed from 18 parts by mass to 35 parts by mass, the amount of decabromodiphenylethane used was changed from 9 parts by mass to 12 parts by mass, and the amount of antimony trioxide used was changed from 3 parts by mass to 4 parts by mass. SMC (R1) was obtained in the same manner as in Example 1, except that the amount of glass fiber used was changed from 70.5 parts by mass to 65.9 parts by mass.

Comparative Example 2 Preparation of Resin Composition (R2) and Production of SMC (R2) Resin composition (R2) was obtained in the same manner as in Example 1, except that in Example 1, the amount of wetting dispersant used was changed from 5 parts by mass to 6 parts by mass, the amount of aluminum hydroxide used was changed from 70 parts by mass to 30 parts by mass, the amount of glass balloons used was changed from 18 parts by mass to 24 parts by mass, the amount of decabromodiphenylethane used was changed from 9 parts by mass to 6 parts by mass, and the amount of antimony trioxide used was changed from 3 parts by mass to 2 parts by mass. SMC (R2) was obtained in the same manner as in Example 1, except that the amount of glass fiber used was changed from 70.5 parts by mass to 58.2 parts by mass.

[Method for evaluating light weight]
The SMC obtained in the examples and comparative examples was peeled off, cut to 265 mm x 265 mm, and three of these were stacked and set in the center of a 30 x 30 ^cm2 flat plate mold, and molded at a press mold temperature of 150°C, a press time of 5 minutes, and a press pressure of 12 MPa to obtain a flat plate-shaped molded product with a thickness of 3 mm. This molded product was cut to 40 mm x 40 mm, and the specific gravity of the molded product was measured using an electronic specific gravity meter and evaluated as follows.
"Good": The specific gravity of the molded article is 1.3 or less.
"X": The specific gravity of the molded product exceeds 1.3.

[Method of evaluating manufacturability]
In the examples and comparative examples, a resin composition containing glass fibers was prepared at 30° C., 1 ml of the composition was sampled, and the viscosity was measured using a cone-plate viscometer (40P cone, rotor rotation speed: 50 rpm). The viscosity was evaluated as follows.
"Good": Viscosity is 26 Pa·s or less.
"X": Viscosity exceeds 26 Pa·s.

[Flame retardancy evaluation method]
The SMC obtained in the examples and comparative examples was peeled off, cut into 265 mm x 265 mm pieces, and three pieces were stacked and set in the center of a 30 x 30 ^cm2 flat plate mold, and molded at a press mold temperature of 150°C, a press time of 5 minutes, and a press pressure of 12 MPa to obtain a flat plate-shaped molded product with a thickness of 3 mm. This was subjected to a combustion test; UL-94V test, and was evaluated as follows.
"〇"; V-0
"x": V-1 or less

As shown in Examples 1 to 6, the resin composition of the present invention was found to have excellent viscosity, flame retardancy, and lightweight properties that make it suitable for manufacturing.

On the other hand, in Comparative Example 1, the amount of wetting and dispersing agent (B) used exceeded the range specified in the present invention, but the flame retardancy and manufacturing suitability were poor.

In Comparative Example 2, the amount of flame retardant (D) used was below the range specified in the present invention, but the flame retardancy was poor.

Claims (3)

A sheet molding compound comprising a resin composition including a resin component (A) including an unsaturated polyester resin (a1) and styrene (a2), and a reinforcing fiber (F) ,
Relative to 100 parts by mass of the resin component (A),
1 to 6 parts by mass of a wetting and dispersing agent (B),
15 to 40 parts by mass of glass balloons (C),
The flame retardant (D) is contained in an amount of 10 to 30 parts by mass ,
The flame retardant (D) is at least one selected from the group consisting of bromine-based flame retardants, antimony trioxide, red phosphorus-based flame retardants, and nitrogen-based flame retardants;
The reinforcing fiber (F) is at least one selected from the group consisting of glass fiber and carbon fiber,
A sheet molding compound , characterized in that the specific gravity of the resulting molded article is 1.3 or less . The sheet molding compound according to claim 1, further comprising an inorganic filler (E) selected from the group consisting of aluminum hydroxide, calcium carbonate, sodium hydroxide, clay, talc, kaolin, and silica in an amount of 20 to 80 parts by mass per 100 parts by mass of the resin component ( A ). A molded product made from the sheet molding compound according to claim 1 or 2 .