SMC sheets and its prepn. method

A sheet and core material technology, applied in the field of SMC sheet and its preparation, can solve the problems of poor product surface quality, poor flow performance, large post-repairing workload, etc., achieve good gloss, improve production efficiency, reduce curing Effects of time and molding temperature

Inactive Publication Date: 2007-01-31
北京玻钢院复合材料有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] At present, most of the sheets in the market are pressed to produce more defects, such as: more pinholes, poor fluidity, poor surface quality, and a large amount of post-repair work, etc.

Method used

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  • SMC sheets and its prepn. method
  • SMC sheets and its prepn. method
  • SMC sheets and its prepn. method

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Experimental program
Comparison scheme
Effect test

preparation example Construction

[0045] The third step: the preparation method of the SMC sheet, comprising the following steps:

[0046] 1) According to the order of unsaturated polyester resin, low shrinkage additive, internal mold release agent and calcium carbonate, add in sequence in proportion, after mixing evenly, add styrene, initiator and magnesium oxide, mix and stir evenly to make resin paste; According to the special requirements of the process, color paste and / or additives can also be added in proportion to the resin paste;

[0047] Component A composed of unsaturated polyester resin, low-shrinkage additive, internal mold release agent, calcium carbonate, etc. requires sufficient stirring time so that each component can be mixed evenly to avoid product defects. Component B composed of styrene, initiator and magnesium oxide should be added before production, and the amount added should be accurate. At the same time, it is required to ensure sufficient stirring time, but the stirring time should not ...

Embodiment 1

[0052] Embodiment 1: SMC sheets of different low-shrinkage additives

[0053] Low-shrinkage additives are the most important factor in determining the surface quality of products, and are also the main determinant of the cost of SMC sheets. Depending on the application in different auto parts, the required shrinkage rate is different, and the selection of different low-shrinkage additives will have different effects on SMC sheets.

[0054] Step 1: Prepare the resin paste

[0055] Resin paste composition (parts by weight):

[0056] Composition of component A:

[0057] Ortho-phthalic resin: 60 parts

[0058] PVAc: 40 parts

[0059] Zinc stearate: 3.5 parts

[0060] BYKW-972: 1 part

[0061] 325 mesh calcium carbonate: 80 parts

[0062] 600 mesh calcium carbonate: 40 parts

[0063] Composition of component B:

[0064] Styrene: 5 parts

[0065] TBPB: 1 serving

[0066] Magnesium oxide: 1.4 parts

[0067] Titanium white paste: 1 part

[0068] When preparing the resin p...

Embodiment 2

[0077] Embodiment 2: the influence of filler on SMC sheet

[0078] In the SMC process, the filler system plays an increasingly important role in improving the performance of the resin system and the final performance of the product. The main function of the filler is to reduce the cost of materials, improve the manufacturability of SMC manufacturing and molding, and improve various related properties of SMC products, such as surface properties, electrical properties, flame retardant properties, mechanical properties, etc. Under the condition of high filler content, the smaller the particle size of the filler, the smaller the apparent viscosity of the SMC resin paste and the higher the surface quality. Therefore, to maximize the benefits of fillers in SMC, careful consideration must be given to the type, amount and grade of material. In the present invention, calcium carbonate is adopted as a filler, and suitable fillers and consumption are selected by affecting the particle s...

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Abstract

A SMC sheet with high surface quality and luster is composed of both surficial PE films and a core material prepared from glass fibers through immersing them in the resin paste which is proportionally from unsaturated polyester resin, low-shrinkage additive, internal demoulding agent, calcium carbonate, styrene, trigger and magnesium oxide.

Description

technical field [0001] The invention relates to an SMC sheet and a preparation method thereof. Background technique [0002] "SMC" is the English abbreviation of Sheet Molding Compound, the middle core material is composed of glass fiber impregnated with resin paste, and the upper and lower sides are covered with PE film; among them, the resin paste contains unsaturated polyester resin, low Various components such as shrinkage additives, internal mold release agents, fillers, styrene, initiators, thickeners, color pastes, etc., form a "sandwich structure". The production and molding process of SMC is roughly as follows: put the glass fiber on the PE film uniformly coated with resin paste in advance, and then cover it with another layer of PE film coated with resin paste. Winding, then thickened at a certain temperature to make it non-sticky, and then molded. SMC sheets first appeared in Europe in the 1960s, and then the United States, Japan and other countries successively...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B32B17/04B32B17/10B32B27/04B32B27/18
Inventor 薛忠民陈淳李永国高红梅汪照军
Owner 北京玻钢院复合材料有限公司
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