Low-voc natural fiber composite material, preparation method therefor and application thereof

Abstract

The present invention relates to a low-volatile organic compound (VOC) natural fiber composite material, a preparation method therefor and an application thereof. In the method, a nanoclay and a resin are blend-spun to prepare modified synthetic fibers, the modified synthetic fibers are mixed with natural fibers or with natural fibers and other fibers to prepare mixed fibers, and the mixed fibers are shredded, mixed, lapped, needle punched or hot pressed, so as to prepare the low-VOC natural fiber composite material. The low-VOC natural fiber composite material can be applied to automobile interior trims after hot pressing. The low-VOC natural fiber composite material has features of low VOC, low density, light weight, low cost, high strength, good toughness, high deformability, high safety, and being environmentally-friendly and recyclable.

What is claimed is: 
     
         1 . A method for preparing a low-volatile organic compound (VOC) natural fiber composite material, comprising:
 step S 1 : blend-spinning a nanoclay and a resin to prepare modified synthetic fibers; and   step S 2 : mixing the modified synthetic fibers with natural fibers or with natural fibers and other fibers to prepare mixed fibers, thereby forming the low-VOC natural fiber composite material.   
     
     
         2 . The preparation method according to  claim 1 , wherein after the step S 2 , the method further comprises:
 step S 3 : spraying a nanoclay-coupling agent liquid mixture into the mixed fibers, thereby forming the low-VOC natural fiber composite material.   
     
     
         3 . The preparation method according to  claim 1 , wherein the step S 1  comprises:
 blend-pelletizing a nanoclay and resin particles at a high temperature to prepare nanocomposite resin particles; 
 blend-spinning nanocomposite resin particles and resin particles of the same kind to prepare modified synthetic fibers. 
 
     
     
         4 . The preparation method according to  claim 1 , wherein in the step S 1 , the nanoclay is 0.1%-2% of the total weight of the modified synthetic fibers. 
     
     
         5 . The preparation method according to  claim 1 , wherein the nanoclay used in the step S 1  is nano-montmorillonite or inorganic particles having an absorption function, and the nanoclay has a particle size in the range of 2-10 μm. 
     
     
         6 . The preparation method according to  claim 1 , wherein the resin used in the step S 1  is a thermoplastic polymer material. 
     
     
         7 . The preparation method according to  claim 6 , wherein the thermoplastic polymer material is one or more selected from the group consisting of polyethylene, polypropylene, polylactic acid, a polyester material, polyethylene terephthalate and a polyamide material. 
     
     
         8 . The preparation method according to  claim 1 , wherein in the step S 2 , the modified synthetic fibers are 30-70% of the total weight of the mixed fibers, and the natural fibers or the natural fibers and other fibers are 70-30% of the total weight of the mixed fibers, preferably wherein in the step S 2 , the modified synthetic fibers are 50% of the total weight of the mixed fibers, and the natural fibers or the natural fibers and other fibers are 50% of the total weight of the mixed fibers. 
     
     
         9 . The preparation method according to  claim 1 , wherein the natural fibers and the other fibers are mixed at a mass ratio of 9:1 to 1:9. 
     
     
         10 . The preparation method according to  claim 1 , wherein the natural fibers are one or a mixture of hemp, jute, linen, ramie, kenaf, cotton, kapok fibers, and sisal fibers, and the other fibers are one or a mixture of glass fibers and basalt fibers. 
     
     
         11 . The preparation method according to  claim 2 , wherein in the step S 3 , a method for preparing the nanoclay-coupling agent liquid mixture comprises:
 adding 0.5-2% of the nanoclay, 0.25-1% of a dispersant, and 1-2% of a silane coupler based on the total weight of the mixed fibers into water to form a nanoclay-coupling agent suspension having a concentration of 10-30%;   stirring the nanoclay-coupling agent suspension at 1000-1350 rpm for 0.5-2 h; and   stirring the nanoclay-coupling agent suspension at 1700-2000 rpm for 1.5-3 h, thus forming the nanoclay-coupling agent liquid mixture.   
     
     
         12 . The preparation method according to  claim 2 , wherein the step S 3  further comprises:
 spraying, in a shredding or mixing stage in a nonwoven process, the nanoclay-coupling agent liquid mixture into the mixed fibers for blending; 
 shredding, mixing, lapping and needle punching the mixed fibers mixed with the nanoclay-coupling agent liquid mixture, to prepare the low-VOC natural fiber composite material; and/or performing hot pressing treatment on the low-VOC natural fiber composite material to prepare a low-VOC natural fiber composite mat or prepressing plate having a surface density of 500-4000 g/m 2 , preferably wherein for the hot pressing treatment, the preheating temperature is 190-230° C., the preheating time is 20-120 s, and the dwell time is 20-90 s. 
 
     
     
         13 . A low-VOC natural fiber composite material prepared using the preparation method according to  claim 1 . 
     
     
         14 . A method for preparation of automobile interior trims, comprising the step of preparing a low-VOC natural fiber composite material  claim 1 . 
     
     
         15 . The method according to  claim 14 , comprising the following steps:
 step S 11 : mixing the low-VOC natural fiber composite material with polypropylene fibers and wood fibers to form a matrix;   step S 12 : laying a surface decorative layer on a side surface of the matrix to form a composite mat material; and   step S 13  : die-forming the composite mat material, preferably wherein the step S 13  further comprises:   tailoring and blanking the composite mat material according to a designed shape, and then heating and softening the composite mat material in a heating apparatus at 200-220° C.; and   placing the softened mat material into a mold for press molding at a pressure of 30 KN/cm 2  for a dwell time of 3-5 minutes, and removing the mold to obtain the finished product.