Low-density low-pressure sheet molding compound and preparation method thereof

Abstract

The invention provides a low-density low-pressure sheet molding compound and a preparation method thereof. The invention discloses a low-density low-pressure sheet molding compound. The composite material is prepared from the following components in parts by weight: 55 to 65 parts of unsaturated polyester resin, 30 to 40 parts of low-shrinkage additive, 6 to 8 parts of styrene, 3.5 to 4.5 parts ofthickening agent, 1 to 2 parts of benzoyl peroxide tert-butyl ester, 4 to 6 parts of light zinc stearate, 70 to 80 parts of calcium carbonate, 20 to 30 parts of hollow glass beads and 45 to 55 partsof chopped glass fibers. According to the invention, a low-pressure sheet molding compound (LPMC) technology is adopted; mutual cooperation of components, therefore, the sheet molding compound prepared by the invention has lower density and the forming pressure can be greatly reduced; the magnesium oxide paste and the crystalline resin are used as a combined thickening system, so that the materialis formed under low pressure; the hollow glass beads are used as a filling material, so that the material density and the heat conductivity coefficient are reduced; the density of the sheet molding compound is 1.216-1.330 g / cm<3>, the heat conductivity coefficient of the sheet molding compound is 0.288-0.347 W / m.K, and the bending strength of the sheet molding compound is 59.15-82.39 Mpa.

Description

technical field

[0001] The invention relates to the technical field of sheet molding compounds, in particular to a low-density, low-pressure sheet molding compound and a preparation method thereof. Background technique

[0002] Sheet molding compound (SMC) has many advantages such as high specific strength, high degree of mechanization, and low cost, and its application has spread all over the fields of automobile, electric power, military industry, chemical industry, and rail transit.

[0003] On the one hand, SMC is generally formed under high pressure (5-15Mpa), which has strict requirements on molds and equipment. Production requires a large-tonnage flat press that can generate and resist high pressure, and a large-tonnage and efficient press It is expensive and occupies a large area, which undoubtedly greatly increases the investment in equipment and the area used in the factory building, which increases the cost. In addition, the mold of traditional SMC needs to use hi...

Examples

Embodiment 1

[0030] A low-density, low-pressure sheet molding compound, comprising the following components by weight: unsaturated polyester resin: 55 parts, low-shrinkage additive: 33 parts, styrene: 6.5 parts, magnesium oxide paste: 2 parts, crystallization Resin: 2.5 parts, tert-butyl benzoyl peroxide: 1.4 parts, light zinc stearate: 4 parts, calcium carbonate: 80 parts, hollow glass microspheres: 30 parts, chopped glass fiber: 50 parts. Among them, the density of hollow glass microspheres is 0.38-0.42g / cm 3 The density of magnesium oxide paste is 1.65g / ml, and the viscosity is 17000mpa s; the melting point of crystalline resin is about 55°C, and the particle size is 200-400 mesh; chopped glass fiber is obtained by cutting glass fiber, and its length is 3- 5cm.

[0031] The above-mentioned low-density and low-pressure sheet molding compound is specifically prepared by the following method:

[0032] 1) According to the above component formula, weigh each raw material, disperse benzoyl ...

Embodiment 2

[0036] A low-density low-pressure sheet molding compound, comprising the following components in parts by weight: unsaturated polyester resin: 64 parts, low shrinkage additive: 38 parts, styrene: 7.5 parts, magnesium oxide paste: 1.5 parts, crystallization Resin: 2 parts, tert-butyl benzoyl peroxide: 1.7 parts, light zinc stearate: 6 parts, calcium carbonate: 70 parts, hollow glass microspheres: 30 parts, chopped glass fiber: 55 parts. Among them, the density of hollow glass microspheres is 0.38-0.42g / cm 3 The density of magnesium oxide paste is 1.65g / ml, and the viscosity is 17000mpa s; the melting point of crystalline resin is about 55°C, and the particle size is 200-400 mesh; chopped glass fiber is obtained by cutting glass fiber, and its length is 3- 5cm.

[0037] The above-mentioned low-density and low-pressure sheet molding compound is specifically prepared by the following method:

[0038] 1) According to the above component formula, weigh each raw material, disperse ...

Embodiment 3

[0042] A low-density, low-pressure sheet molding compound, comprising the following components in parts by weight: unsaturated polyester resin: 60 parts, low shrinkage additive: 35 parts, styrene: 7 parts, magnesium oxide paste: 1.5 parts, crystallization Resin: 2 parts, tert-butyl benzoyl peroxide: 1.5 parts, light zinc stearate: 5 parts, calcium carbonate: 75 parts, hollow glass microspheres: 25 parts, chopped glass fiber: 52 parts. Among them, the density of hollow glass microspheres is 0.38-0.42g / cm 3 The density of magnesium oxide paste is 1.65g / ml, and the viscosity is 17000mpa s; the melting point of crystalline resin is about 55°C, and the particle size is 200-400 mesh; chopped glass fiber is obtained by cutting glass fiber, and its length is 3- 5cm.

[0043] The above-mentioned low-density and low-pressure sheet molding compound is specifically prepared by the following method:

[0044] 1) According to the above component formula, weigh each raw material, disperse ben...

technical field

[0001] The invention relates to the technical field of sheet molding compounds, in particular to a low-density, low-pressure sheet molding compound and a preparation method thereof. Background technique

[0002] Sheet molding compound (SMC) has many advantages such as high specific strength, high degree of mechanization, and low cost, and its application has spread all over the fields of automobile, electric power, military industry, chemical industry, and rail transit.

[0003] On the one hand, SMC is generally formed under high pressure (5-15Mpa), which has strict requirements on molds and equipment. Production requires a large-tonnage flat press that can generate and resist high pressure, and a large-tonnage and efficient press It is expensive and occupies a large area, which undoubtedly greatly increases the investment in equipment and the area used in the factory building, which increases the cost. In addition, the mold of traditional SMC needs to use hi...

Examples

Embodiment 1

[0030] A low-density, low-pressure sheet molding compound, comprising the following components by weight: unsaturated polyester resin: 55 parts, low-shrinkage additive: 33 parts, styrene: 6.5 parts, magnesium oxide paste: 2 parts, crystallization Resin: 2.5 parts, tert-butyl benzoyl peroxide: 1.4 parts, light zinc stearate: 4 parts, calcium carbonate: 80 parts, hollow glass microspheres: 30 parts, chopped glass fiber: 50 parts. Among them, the density of hollow glass microspheres is 0.38-0.42g / cm 3 The density of magnesium oxide paste is 1.65g / ml, and the viscosity is 17000mpa s; the melting point of crystalline resin is about 55°C, and the particle size is 200-400 mesh; chopped glass fiber is obtained by cutting glass fiber, and its length is 3- 5cm.

[0031] The above-mentioned low-density and low-pressure sheet molding compound is specifically prepared by the following method:

[0032] 1) According to the above component formula, weigh each raw material, disperse benzoyl ...

Embodiment 2

[0036] A low-density low-pressure sheet molding compound, comprising the following components in parts by weight: unsaturated polyester resin: 64 parts, low shrinkage additive: 38 parts, styrene: 7.5 parts, magnesium oxide paste: 1.5 parts, crystallization Resin: 2 parts, tert-butyl benzoyl peroxide: 1.7 parts, light zinc stearate: 6 parts, calcium carbonate: 70 parts, hollow glass microspheres: 30 parts, chopped glass fiber: 55 parts. Among them, the density of hollow glass microspheres is 0.38-0.42g / cm 3 The density of magnesium oxide paste is 1.65g / ml, and the viscosity is 17000mpa s; the melting point of crystalline resin is about 55°C, and the particle size is 200-400 mesh; chopped glass fiber is obtained by cutting glass fiber, and its length is 3- 5cm.

[0037] The above-mentioned low-density and low-pressure sheet molding compound is specifically prepared by the following method:

[0038] 1) According to the above component formula, weigh each raw material, disperse ...

Embodiment 3

[0042] A low-density, low-pressure sheet molding compound, comprising the following components in parts by weight: unsaturated polyester resin: 60 parts, low shrinkage additive: 35 parts, styrene: 7 parts, magnesium oxide paste: 1.5 parts, crystallization Resin: 2 parts, tert-butyl benzoyl peroxide: 1.5 parts, light zinc stearate: 5 parts, calcium carbonate: 75 parts, hollow glass microspheres: 25 parts, chopped glass fiber: 52 parts. Among them, the density of hollow glass microspheres is 0.38-0.42g / cm 3 The density of magnesium oxide paste is 1.65g / ml, and the viscosity is 17000mpa s; the melting point of crystalline resin is about 55°C, and the particle size is 200-400 mesh; chopped glass fiber is obtained by cutting glass fiber, and its length is 3- 5cm.

[0043] The above-mentioned low-density and low-pressure sheet molding compound is specifically prepared by the following method:

[0044] 1) According to the above component formula, weigh each raw material, disperse ben...

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