KR101350949B1 - Hemp fiber for plastic reinforcement and preparation method thereof - Google Patents

Abstract

The present invention relates to a hemp fiber for plastic reinforcement and a method of manufacturing the same. The hemp fiber is composed of the following components by weight: 100 parts by weight of chopped hemp fiber, 0.1 to 100 parts by weight of hemp fiber treatment agent, 1 to 10 parts by weight of functional polyolefin wax, 0.1 to 10 parts by weight of a coupling agent (coupling agent) And 0.1 to 0.5 parts by weight of antioxidant. The method comprises the following steps: first, cutting the cut hemp fibers, immersing them in sodium hydroxide solution, stirring the mixture, washing and drying the water, and then grinding the hemp fibers Immersing in an aqueous treatment agent solution and then drying them to obtain a surface treated cut hemp fiber; Secondly, putting the cut hemp fiber, the coupling agent, the functional polyolefin wax, and the antioxidant into a preheated kneader, and kneading the mixture to obtain a plastic reinforcement hemp fiber. The cut hemp fibers according to the present invention provide good color, stiffness and heat resistance as well as good compatibility with plastics and can be used to produce high performance short hemp fiber / plastic composites as reinforcements in plastic matrices.

Description

Hemp fiber for plastic reinforcement and preparation method

The present invention relates to natural fiber composites and wood-plastic composites, and more particularly, to hemp fibers for plastic reinforcement and a method of manufacturing the same.

In recent years, research on natural plant fiber composites and wood-plastic composites has been actively conducted. This is because, on the one hand, the source of natural plant fibers is extensive and inexpensive, and on the other hand, natural plant fiber reinforced plastics tend to replace mineral fiber reinforced plastics in terms of performance.

Most natural plant fibers are made by filamentous or fibrous mats, and then hot press molded with thermoset resins, while they cannot be added directly to thermoplastics like glass fibers and injection molded. On the other hand, natural plant fibers exhibit strong polarity and hydrophilicity due to the high hydroxyl density on the fiber surface, which leads to very poor compatibility of plant fibers with non-polar or weakly polar plastics, and also degrades the performance of the composites thus produced. . On the other hand, plant fiber reinforced plastics are difficult to process, in particular injection molding, because of the high volume and high filler content of plant fibers as well as the strong friction present between fibers and plastics, fibers and fixtures, and fibers. The current major solution for improving the interface compatibility of plant fibers and plastics is to add interfacial compatibilizers. One type is a binder such as a silane binder, a titanium binder, an aluminate binder, a rare earth binder, an isocyanate binder, and the like, and the other type is a graft polymer or copolymer of maleic anhydride and polyolefin. First of all, the binders are mostly in liquid form, low in addition and difficult to uniformly disperse in plant fibers, thus weakening the coupling effect and therefore require special equipment in industrial applications. In addition, graft polymers or copolymers of maleic anhydride and polyolefin are mostly granular, so they are easily dispersed in plastics and vegetable fibers, but have a low graft rate, which negatively affects the improvement of interface bond strength. In addition, composites filled with many plant fibers and plastics also present difficulties in extrusion or injection molding. Various processing aids such as olefin wax, amide wax, stearic acid, zinc stearate, calcium stearate and the like have been developed to solve the processing problem of composite materials of plant fiber and plastic, but adding too many processing aids It will also degrade performance.

The first object of the present invention to solve the problems present in the above-described current technology is to provide a plastic reinforcement hemp fiber.

A second object of the present invention is to provide a method for producing the above-mentioned plastic fiber for reinforcing plastic.

In order to achieve the above object, the present invention provides the following technical solutions: As hemp fiber for plastic reinforcement,

100 parts by weight of chopped hemp fiber;

0.1 to 100 parts by weight of the hemp fiber treatment agent (preferably 10 to 80 parts by weight);

1 to 10 parts by weight of functional polyolefin wax;

0.1 to 10 parts by weight of a coupling agent (coupling agent); And

Hemp fiber for plastic reinforcement, characterized in that consisting of 0.1 to 0.5 parts by weight of antioxidant.

The cut hemp fiber is at least one selected from ramie fiber, flax fiber, sisal fiber, jute fiber, and hemp fiber.

The hemp fiber treatment agent is a urea-formaldehyde resin prepolymer, trimethylol melamine resin or hexamethylol melamine resin.

The functional polyolefin wax is at least one selected from metallocene polyethylene wax, metallocene polypropylene wax, metallocene polyolefin, oxidized metallocene polyolefin wax and metallocene polyolefin wax grafted with maleic anhydride.

The binder is at least one selected from silane binders, titanium binders, aluminum binders, isocyanate binders and rare earth binders.

The antioxidant consists of antioxidant 1010 and antioxidant 168 and the mass ratio of both is 2: 1.

The method for preparing the plastic reinforcement hemp fiber includes the following steps:

(1) hemp fibers were cut into lengths of 1 to 20 mm to obtain chopped hemp fibers, and the chopped hemp fibers were immersed in a sodium hydroxide solution, the mixture was stirred for 1 to 20 minutes, washed with water, After drying, they are immersed in an aqueous solution of hemp fiber treatment agent at a temperature of 80 ~ 90 ℃ for 5 minutes to 30 minutes and dried until the solution is consumed by the hemp fiber to obtain a surface-treated cut hemp fiber; And

(2) putting the surface-treated cut hemp fibers, the binder, the functional polyolefin wax and the antioxidant into a kneader preheated at 70 to 80 ° C. in order to knead the mixture to obtain a plastic reinforcement hemp fiber.

The mass concentration of the sodium hydroxide solution in the step (1) is 1% to 10%, the mass concentration of the hemp fiber treatment solution solution is 10% to 50%, the washing is centrifugal, the drying is the hemp fiber Means that the hemp fibers are dried such that they have a mass water content (normal water content of hemp fiber) of 8% to 15%.

In the step (1), the drying is a vacuum drying method at a temperature of 90 ~ 150 ℃ and the hemp fibers are dried to have a mass moisture content of less than 1%, the washing is until the pH is 7.0 ~ 9.0 This means washing the fibers with water.

In the step (2), the kneading time is 5-10 minutes and the kneading speed is 50-300 rpm.

The principle of the present invention is as follows. Dilute the impurities on the surface of the hemp fiber with dilute alkali and then treat the hemp fibers in an aqueous solution of a treatment agent such as urea-formaldehyde resin prepolymer, trimethylol melamine resin or hexamethylol melamine resin, By reacting hydroxy methyl and coating the surface of the hemp fiber with a layer of urea-formaldehyde resin or melamine resin, the surface polarity of the hemp fiber is reduced and the absorption rate of hemp fiber is also reduced, while the stiffness and heat resistance of hemp fiber are Increases. In addition, the binder helps to improve the compatibility of hemp fibers and plastics, and the functional polyolefin wax also improves lubricity and dispersibility inside hemp fibers.

Compared with existing techniques, the cut hemp fibers according to the present invention not only provide good compatibility with plastics, but also good color, stiffness and heat resistance, and produce high performance short hemp fiber / plastic composites as reinforcements in plastic matrices. Can be used.

Although this invention is demonstrated in more detail using the following preferable embodiment, this invention is not limited to the following preferable embodiment.

Example 1

(1) 100 weight part of ramie fiber is cut | disconnected to length of 1-20 mm, and the cut | laminated fiber is obtained. The cut ramie fibers were immersed in a sodium hydroxide solution (mass concentration 1%), the mixture was stirred for 20 minutes, washed with water to pH = 7.0 and centrifuged to dryness, followed by a hemp fiber treatment agent (80 wt. It is immersed in negative aqueous urea-formaldehyde resin prepolymer) solution (mass concentration 30%) for 30 minutes until the solution is consumed by lami fibers. They are then dried in vacuo at a temperature of 110 ° C. to a mass content of less than 1% to give surface treated cut lamina fibers.

(2) the surface-treated cut ramie fibers, 2 parts by weight of silane binder, 9 parts by weight of functional polyolefin wax (5 parts by weight of metallocene polyethylene wax and 4 parts by weight of maleic anhydride grafted metallocene polyolefin wax Mixture) and 0.4 parts by weight of antioxidant (mass ratio of both with antioxidant 1010 and antioxidant 168 2: 1) were placed in a kneader preheated to 70 ° C. in turn and kneaded the mixture for 5 minutes at a speed of 100 rpm to reinforce plastics. Get Dragon Lami Fiber. The plastic reinforcing ramie fiber thus produced is light yellow, has good rigidity and is easily dispersed in the resin without sticking or twisting together.

Example 2

(1) 100 parts by weight of flax fiber are cut to a length of 1 to 20 mm to obtain cut flax fiber. The cut flax fiber was immersed in a sodium hydroxide solution (mass concentration 10%) and the mixture was stirred for 2 minutes, washed with water to pH = 9.0 and centrifuged to dryness, followed by a hemp fiber treatment agent (90 weight) It is immersed in negative aqueous trimethylol melamine resin) (mass concentration 20%) for 30 minutes until the solution is probably consumed by the fibers. They are then dried in vacuo at a temperature of 150 ° C. to a mass content of flax fibers of less than 1% to obtain cut flax fibers that have been surface treated.

(2) said surface treated chopped flax fiber, 8 parts by weight binder (a mixture of 4 parts titanium binder and 4 parts rare earth binder), 4 parts functional polyolefin wax (2 parts metallocene polypropylene wax and 2 1 part by weight of a mixture of metallocene polyethylene wax) and 0.5 parts by weight of antioxidant (mass ratio 2: 1 with both antioxidant 1010 and antioxidant 168) were placed in a kneader preheated to 80 ° C. in sequence for 10 minutes at a speed of 50 rpm. The mixture is kneaded to obtain flax fiber for plastic reinforcement. The plastic reinforcement flax fibers thus produced are light yellow, stiff and easily disperse in the resin without sticking or twisting together.

Example 3

(1) 100 parts by weight of sisal fibers are cut to a length of 1 to 20 mm to obtain cut sisal fibers. The cleaved sisal fibers were immersed in a sodium hydroxide solution (mass concentration 5%) and the mixture was stirred for 5 minutes, washed with water to pH = 8.0 and centrifuged to dryness, followed by a hemp fiber treatment agent (100). It is immersed in a weight part aqueous solution of hexamethylolmelamine resin (mass concentration 10%) for 20 minutes until the solution is consumed by sisal fibers. They are then dried in vacuo at a temperature of 120 ° C. to a mass content of sisal fibers of less than 1% to obtain cut sisal fibers that have been surface treated.

(2) the surface treated chopped sisal fibers, 7 parts by weight of binder (5 parts by weight of aluminum binder and 2 parts by weight of isocyanate binder), 7 parts by weight of functional polyolefin wax (5 parts by weight of metallocene polyethylene wax and 2 parts by weight) A mixture of oxidized metallocene polyolefin wax) and 0.4 parts by weight of antioxidant (mass ratio 2: 1 between antioxidant 1010 and antioxidant 168) were placed in a kneader preheated to 75 ° C. in sequence for 5 minutes at a speed of 300 rpm. The mixture is kneaded to obtain sisal fibers for plastic reinforcement. The thus prepared plastic reinforcing sisal fibers are light yellow, have good stiffness and are easily dispersed in the resin without sticking or twisting together.

Example 4

(1) 100 parts by weight of jute fiber are cut to a length of 1 to 20 mm to obtain a cut jute fiber. The chopped jute fibers were immersed in a sodium hydroxide solution (mass concentration 3%), the mixture was stirred for 1 minute, washed with water to pH = 7.5 and centrifuged to dryness, and then hemp fiber treatment agent (50 wt. It is immersed in negative aqueous urea-formaldehyde resin prepolymer) solution (mass concentration 30%) for 25 minutes until the solution is consumed by jute fibers. They are then dried in vacuo at a temperature of 100 ° C. to a mass content of less than 1% to obtain a surface treated chopped jute fiber.

(2) said surface treated chopped jute fibers, 8 parts by weight of a binder (a mixture of 5 parts by weight of isocyanate and 3 parts by weight of rare earth binder), 1 part by weight of oxidized metallocene polyolefin wax and 0.3 part by weight of antioxidant (oxidation) Both mass ratios 2: 1) of the inhibitor 1010 and the antioxidant 168 were sequentially placed in a kneader preheated to 78 ° C., and the mixture was kneaded for 8 minutes at a speed of 150 rpm to obtain jute fibers for plastic reinforcement. The plastic reinforcement jute fibers thus prepared are light yellow, have good stiffness and are easily dispersed in the resin without sticking or twisting together.

Example 5

(1) 100 parts by weight of hemp fibers are cut to a length of 1 to 20 mm to obtain cut hemp fibers. The chopped hemp fibers were immersed in a sodium hydroxide solution (mass concentration 8%), the mixture was stirred for 15 minutes, washed with water to pH = 8.5, and centrifuged to dryness, and then hemp fiber treatment agent (20 wt. It is immersed in negative trimethylol melamine resin) aqueous solution (mass concentration 50%) for 15 minutes until it is consumed by hemp fiber. They are then dried in vacuo at a temperature of 90 ° C. to a mass content of less than 1% to obtain cut hemp fibers that have been surface treated.

(2) the surface treated chopped hemp fibers, 0.1 parts by weight of isocyanate binder, 5 parts by weight of functional polyolefin wax (1 part by weight of metallocene polyethylene wax, 2 parts by weight of metallocene polypropylene wax, and 3 parts by weight of maleic acid) A mixture of anhydrous grafted metallocene polyolefin wax) and 0.1 parts by weight of antioxidant (mass ratio 2: 1 with both antioxidant 1010 and antioxidant 168) were placed in a kneader preheated to 76 ° C. in sequence at a speed of 250 rpm. The mixture is kneaded for 8 minutes to obtain hemp fibers for plastic reinforcement. The plastic reinforcement hemp fibers thus prepared are light yellow, have good stiffness and are easily dispersed in the resin without sticking or twisting together.

Example 6

(1) 100 parts by weight of hemp fibers (a mixture of ramie fibers and hemp fibers) are cut to a length of 1 to 20 mm to obtain cut hemp fibers. The chopped hemp fibers were immersed in a sodium hydroxide solution (mass concentration 6%), the mixture was stirred for 12 minutes, washed with water to pH = 7.5, and centrifuged to dryness, and then hemp fiber treatment agent (50 wt. It is immersed in a negative aqueous solution of hexamethylol melamine resin (mass concentration 30%) for 5 minutes until the solution is consumed by the hemp fiber. Thereafter, they were dried in a vacuum at a temperature of 150 ° C. to a mass content of hemp fiber of less than 1% to obtain a surface treated cut hemp fiber.

(2) the surface treated chopped hemp fibers, 10 parts by weight of a binder (2 parts by weight of silane binder, 5 parts by weight of aluminum binder, and 3 parts by weight of rare earth binder), 10 parts by weight of functional polyolefin wax (2 parts by weight of metal A mixture of rosene polyethylene wax, 3 parts by weight of metallocene polypropylene wax, and 3 parts by weight of oxidized metallocene polyolefin wax) and 0.5 parts by weight of antioxidant (antioxidant 1010 and antioxidant 168 with a mass ratio of 2: 1 ) Is placed in a kneader preheated at 72 ° C. in turn to knead the mixture for 7 minutes at a speed of 280 rpm to obtain a plastic reinforcing hemp fiber. The plastic reinforcing hemp fiber thus prepared is light yellow, has good stiffness and is easily dispersed in the resin without sticking or twisting together.

While the present invention has been described with reference to what are presently considered to be the most preferred embodiments, various modifications, substitutions, combinations, and simplifications of the present invention should be considered as equivalent technical solutions, rather than being limited to the above embodiments. It is intended to be included within the scope.

Claims (10)

Hemp fiber for plastic reinforcement,
100 parts by weight of chopped hemp fiber;
0.1 to 100 parts by weight of hemp fiber treatment agent;
1 to 10 parts by weight of functional polyolefin wax;
0.1 to 10 parts by weight of a coupling agent (coupling agent); And
Hemp fiber for plastic reinforcement, characterized in that consisting of 0.1 to 0.5 parts by weight of antioxidant. The fiber of claim 1, wherein the cut hemp fibers are selected from ramie fibers, flax fibers, sisal fibers, jute fibers, and hemp fibers. Hemp fiber for plastic reinforcement, characterized in that at least one. The hemp fiber treatment agent according to claim 1, wherein the hemp fiber treatment agent is urea-formaldehyde resin prepolymer, trimethylol melamine resin or hexamethylol melamine resin. The method of claim 1, wherein the functional polyolefin wax is one or more selected from metallocene polyethylene wax, metallocene polypropylene wax, oxidized metallocene polyolefin wax and metallocene polyolefin wax grafted maleic anhydride. Hemp fiber for plastic reinforcement. The plastic fiber reinforcing hemp fiber according to claim 1, wherein the binder is at least one selected from a silane binder, a titanium binder, an aluminum binder, an isocyanate binder, and a rare earth binder. According to claim 1, wherein the antioxidant is made of antioxidant 1010 and oxidizing agent 168 and the plastic fiber reinforcement hemp fiber, characterized in that the mass ratio of both. As a method of manufacturing plastic fiber hemp fiber according to claim 1,
(1) hemp fibers were cut into lengths of 1 to 20 mm to obtain chopped hemp fibers, and the chopped hemp fibers were immersed in sodium hydroxide solution, the mixture was stirred for 1 to 20 minutes, washed with water, After drying, they are immersed in an aqueous solution of hemp fiber treatment agent at a temperature of 80 ~ 90 ℃ for 5 minutes to 30 minutes and dried until the solution is consumed by the hemp fiber to obtain a surface-treated cut hemp fiber; And
(2) inserting the surface treated cut hemp fibers, the binder, the functional polyolefin wax and the antioxidant into a kneader preheated at 70 to 80 ° C. in order to knead the mixture to obtain a plastic reinforcement hemp fiber. Method for producing a plastic reinforcing hemp fiber comprising a. The mass concentration of the sodium hydroxide solution in the step (1) is 1% to 10%, the mass concentration of the hemp fiber treatment agent solution is 10% to 50%, the washing is centrifugal, The drying is a method of producing a plastic reinforcement hemp fiber, characterized in that for drying the hemp fibers so that the hemp fibers have a mass moisture content of 8% to 15%. The method according to claim 7, wherein the drying in step (1) is a vacuum drying method at a temperature of 90 ~ 150 ℃ and the hemp fibers are dried to have a moisture content of less than 1%, the washing is pH 7.0 ~ 9.0 Method of producing a plastic reinforcement hemp fiber, characterized in that to wash the hemp fibers with water until this. 8. The method of claim 7, wherein the kneading time is 5 to 10 minutes and the kneading speed is 50 to 300 rpm in the step (2).