阅读说明：本技术 一种皮芯纤维/碳纤维热塑性复合材料及其制备方法 (Sheath-core fiber/carbon fiber thermoplastic composite material and preparation method thereof ) 是由 许跃 刘�文 杜齐 于 2020-03-09 设计创作，主要内容包括：本发明涉及制浆造纸技术领域,提供了一种皮芯纤维/碳纤维热塑性复合材料及其制备方法,本发明提供的制备方法以皮芯纤维和碳纤维为原料,在制备过程中,皮芯纤维的皮层熔化,将皮芯纤维和碳纤维充分粘结,替代传统方法中的预浸料,有效提高了制备得到的皮芯纤维/碳纤维热塑性复合材料的力学性能。与传统方法相比,本发明提供的方法省去了预浸料的步骤,方法更加简单,更加环保。(The invention relates to the technical field of pulping and papermaking, and provides a sheath-core fiber/carbon fiber thermoplastic composite material and a preparation method thereof. Compared with the traditional method, the method provided by the invention omits the step of prepreg, is simpler and more environment-friendly.)

1. A preparation method of a sheath-core fiber/carbon fiber thermoplastic composite material comprises the following steps:

(1) mixing sheath-core fiber, carbon fiber, a defoaming agent and water, and then performing dispersion treatment to obtain slurry; the melting point of the sheath layer of the sheath-core fiber is 90-130 ℃;

(2) sequentially carrying out dehydration forming, squeezing, drying, reeling and slitting on the obtained slurry to obtain a mould pressing original sheet;

(3) stacking a plurality of mould pressing original sheets together, and then sequentially carrying out mould pressing, preheating, heat preservation, pressure maintaining and cooling to obtain a skin-core fiber/carbon fiber thermoplastic composite material;

the number of the plurality of mould pressing original sheets is 1-50.

2. The preparation method according to claim 1, wherein the mass ratio of the sheath-core fiber to the carbon fiber in the step (1) is 50-95: 5-15; the mass of the defoaming agent is 0.1-1.5% of the mass of the oven-dried slurry.

3. The preparation method according to claim 1, wherein the concentration of the slurry on the net in the step (1) is 0.01-0.1 wt%.

4. The preparation method according to any one of claims 1 to 3, wherein the sheath-core fiber in the step (1) is a composite polyester fiber and/or an ES fiber;

the sheath layer of the ES fiber is polyethylene, and the core layer is polypropylene and/or polyester.

5. The production method according to any one of claims 1 to 3, wherein the length of the sheath-core fiber in the step (1) is 1 to 20 mm; the length of the carbon fiber is 3-15 mm.

6. The method according to claim 1, wherein the molded base sheet obtained in the step (2) has a basis weight of 50 to 250g/m²。

7. The method according to claim 1, wherein the drying temperature in the step (2) is dependent on the type of the core-sheath fiber,

when the sheath-core fiber is the composite polyester fiber, the drying temperature is 90-110 ℃;

when the sheath-core fiber is ES fiber, the drying temperature is 100-130 ℃;

when the sheath-core fiber is a mixture of the composite polyester fiber and the ES fiber, the drying temperature is 100-120 ℃.

8. The production method according to claim 1, wherein the temperature of the preheating in the step (3) is related to the kind of the sheath-core fiber,

when the sheath-core fiber is the composite polyester fiber, the preheating temperature is 80-100 ℃;

when the sheath-core fiber is the ES fiber, the preheating temperature is 100-120 ℃;

when the sheath-core fiber is a mixture of the composite polyester fiber and the ES fiber, the preheating temperature is 90-110 ℃.

9. The preparation method according to claim 1, wherein the pressure for heat preservation and pressure holding in the step (3) is 0.5 to 10 MPa;

the temperature of the heat preservation and pressure maintaining is related to the type of the sheath-core fiber,

when the sheath-core fiber is the composite polyester fiber, the temperature for heat preservation and pressure maintaining is 160-240 ℃;

when the sheath-core fiber is ES fiber, the temperature for heat preservation and pressure maintaining is 120-150 ℃;

when the sheath-core fiber is a mixture of the composite polyester fiber and the ES fiber, the temperature for heat preservation and pressure maintaining is 140-180 ℃.

10. The sheath-core fiber/carbon fiber thermoplastic composite material prepared by the preparation method of any one of claims 1 to 9.

Technical Field

The invention relates to the technical field of pulping and papermaking, in particular to a sheath-core fiber/carbon fiber thermoplastic composite material and a preparation method thereof.

Background

The carbon fiber reinforced resin matrix Composite (CFRP) is prepared by taking an organic polymer material as a matrix and carbon fibers as a reinforcing material through a composite process. As an advanced composite material, CFRP is widely used in the fields of aerospace, transportation, structural reinforcement engineering, leisure articles and the like due to the excellent characteristics of light weight, high strength, fatigue resistance, corrosion resistance, high temperature resistance, easy processing and forming and the like. With the improvement of the efficiency and the reduction of the manufacturing cost of the CFRP manufacturing method in future, the market demand of the CFRP manufacturing method is continuously expanded, and the application field of the CFRP manufacturing method is continuously widened.

CFRP is classified into two major categories, thermosetting resin composites and thermoplastic resin composites, depending on the matrix resin used, with thermoplastic resin composites having wider applications. The resin matrix of the thermoplastic resin composite material is generally polypropylene (PP), Polyamide (PA), Polycarbonate (PC), Polyetherimide (PEI), Polyphenylene Sulfide (PPs), polyether ether ketone (PEEK), or the like. Since the melt viscosity of the thermoplastic resin matrix generally exceeds 100Pa · s, it is difficult to achieve good impregnation of the carbon fibers, which in turn affects the mechanical properties of the thermoplastic resin composite material obtained.

Disclosure of Invention

In order to solve the technical problems, the invention provides a sheath-core fiber/carbon fiber thermoplastic composite material and a preparation method thereof, the sheath-core fiber/carbon fiber thermoplastic composite material provided by the invention has the bending strength of 250MPa, the tensile strength of 150MPa, and the notch impact toughness of 80kJ/m²。

The invention provides a preparation method of a sheath-core fiber/carbon fiber thermoplastic composite material, which comprises the following steps:

(1) mixing sheath-core fiber, carbon fiber, a defoaming agent and water, and then performing dispersion treatment to obtain slurry; the melting point of the sheath layer of the sheath-core fiber is 90-130 ℃;

(2) sequentially carrying out dehydration forming, squeezing, drying, reeling and slitting on the obtained slurry to obtain a mould pressing original sheet;

(3) stacking a plurality of mould pressing original sheets together, and then sequentially carrying out mould pressing, preheating, heat preservation, pressure maintaining and cooling to obtain a skin-core fiber/carbon fiber thermoplastic composite material;

the number of the plurality of mould pressing original sheets is 1-50.

Preferably, the mass ratio of the sheath-core fibers to the carbon fibers in the step (1) is 50-95: 5-15; the mass of the defoaming agent is 0.1-1.5% of the mass of the oven-dried slurry.

Preferably, the concentration of the upper net of the slurry in the step (1) is 0.01-0.1 wt%.

Preferably, the sheath-core fiber in the step (1) is a composite polyester fiber and/or an ES fiber;

the sheath layer of the ES fiber is polyethylene, and the core layer is polypropylene and/or polyester.

Preferably, the length of the sheath-core fiber in the step (1) is 1-20 mm; the length of the carbon fiber is 3-15 mm.

Preferably, the quantitative amount of the molded original sheet obtained in the step (2) is 50-250 g/m²。

Preferably, the drying temperature in the step (2) is related to the type of the sheath-core fiber,

when the sheath-core fiber is the composite polyester fiber, the drying temperature is 90-110 ℃;

when the sheath-core fiber is ES fiber, the drying temperature is 100-130 ℃;

when the sheath-core fiber is a mixture of the composite polyester fiber and the ES fiber, the drying temperature is 100-120 ℃.

Preferably, the temperature of the preheating in the step (3) is related to the type of the sheath-core fiber,

when the sheath-core fiber is the composite polyester fiber, the preheating temperature is 80-100 ℃;

when the sheath-core fiber is the ES fiber, the preheating temperature is 100-120 ℃;

when the sheath-core fiber is a mixture of the composite polyester fiber and the ES fiber, the preheating temperature is 90-110 ℃.

Preferably, the pressure for heat preservation and pressure maintaining in the step (3) is 0.5-10 MPa;

the temperature of the heat preservation and pressure maintaining is related to the type of the sheath-core fiber,

when the sheath-core fiber is the composite polyester fiber, the temperature for heat preservation and pressure maintaining is 160-240 ℃;

when the sheath-core fiber is ES fiber, the temperature for heat preservation and pressure maintaining is 120-150 ℃;

when the sheath-core fiber is a mixture of the composite polyester fiber and the ES fiber, the temperature for heat preservation and pressure maintaining is 140-180 ℃.

The invention also provides the sheath-core fiber/carbon fiber thermoplastic composite material prepared by the preparation method in the technical scheme.

Advantageous effects

The invention provides a preparation method of a sheath-core fiber/carbon fiber thermoplastic composite material, which takes sheath-core fibers as raw materials, and controls the melting point of the sheath layer of the sheath-core fibers within the range of 90-130 ℃, so that the sheath layer of the sheath-core fibers is melted in the preparation process, the sheath-core fibers and the carbon fibers are fully bonded, the prepreg in the traditional method is replaced, and the mechanical property of the sheath-core fiber/carbon fiber thermoplastic composite material is effectively improved. Compared with the traditional method, the method provided by the invention omits the step of prepreg, is simpler and more environment-friendly.

The invention also provides the sheath-core fiber/carbon fiber thermoplastic composite material prepared by the method, and the sheath-core fiber and the carbon fiber in the sheath-core fiber/carbon fiber thermoplastic composite material provided by the invention are uniformly dispersed, so that the mechanical property of the sheath-core fiber/carbon fiber thermoplastic composite material is effectively improved. The results of the examples show that the bending strength of the sheath-core fiber/carbon fiber thermoplastic composite material prepared by the invention can reach 250MPa, the tensile strength can reach 150MPa, and the notch impact toughness can reach 80kJ/m²。

Detailed Description

The invention provides a preparation method of a sheath-core fiber/carbon fiber thermoplastic composite material, which comprises the following steps:

(1) mixing sheath-core fiber, carbon fiber, a defoaming agent and water, and then performing dispersion treatment to obtain slurry; the melting point of the sheath layer of the sheath-core fiber is 90-130 ℃;

(2) sequentially carrying out dehydration forming, squeezing, drying, reeling and slitting on the obtained slurry to obtain a mould pressing original sheet;

(3) stacking a plurality of mould pressing original sheets together, and then sequentially carrying out mould pressing, preheating, heat preservation, pressure maintaining and cooling to obtain a skin-core fiber/carbon fiber thermoplastic composite material;

the number of the plurality of mould pressing original sheets is 1-50.

The invention mixes the sheath-core fiber, the carbon fiber, the defoamer and the water and then carries out dispersion treatment to obtain the slurry.

In the present invention, all the raw materials are commercially available products unless otherwise specified.

In the present invention, the sheath-core fiber is preferably a composite polyester fiber and/or an ES fiber; when the sheath-core fiber is preferably a mixture of the composite polyester fiber and the ES fiber, the mass ratio of the composite polyester fiber to the ES fiber in the mixture is not particularly required, and any ratio can be adopted. In the invention, the composite polyester fiber is a commercial product, preferably Japanese imperial TJ04CN, and the skin layer melting point of the composite polyester fiber is preferably 90-110 ℃; the sheath layer of the ES fiber is polyethylene, the core layer is preferably polypropylene and/or polyester, and the melting point of the sheath layer of the ES fiber is preferably 100-130 ℃. In the invention, the length of the sheath-core fiber is preferably 1-20 mm, and more preferably 3-18 mm.

In the invention, the length of the carbon fiber is preferably 3-15 mm, and more preferably 3-10 mm; the grade of the carbon fiber is preferably T400, T700, T800 or T1000.

In the invention, the mass ratio of the sheath-core fiber to the carbon fiber is preferably 50-95: 5-15. The invention preferably controls the mass ratio of the sheath-core fiber to the carbon fiber within the range, can fully mix the sheath-core fiber and the carbon fiber, and is beneficial to improving the mechanical property of the sheath-core fiber/carbon fiber thermoplastic composite material.

In the present invention, the defoaming agent is preferably a silicone defoaming agent, a polyether defoaming agent, or a mixture of a silicone defoaming agent and a polyether defoaming agent. In the invention, the mass of the defoaming agent is preferably 0.1-1.5% of the mass of the absolutely dry slurry of the slurry, and more preferably 0.5-1%. In the invention, the use of the defoaming agent can relieve the floating problem in the process of making paper by using the sheath-core fiber, and then the problem of fiber dispersion is solved.

The invention mixes the sheath-core fiber, the carbon fiber, the defoamer and the water and then carries out dispersion treatment to obtain the slurry. In the present invention, the dispersion treatment is preferably performed in a hydraulic disperser, and the time of the dispersion treatment is preferably 1 min. In the present invention, the concentration of the crushed pulp is preferably 3 to 4 wt%. In the invention, the concentration of the upper net of the slurry is preferably 0.01-0.1 wt%.

After the slurry is obtained, the obtained slurry is subjected to dehydration forming, squeezing, drying, reeling and slitting in sequence to obtain the die pressing original sheet. The present invention is not particularly limited to the specific embodiments of dewatering formation and pressing, and may be practiced in a manner well known to those skilled in the art. In the invention, the quantitative ratio of the molded original sheet is preferably 50-250 g/m²。

In the present invention, the temperature of the drying is preferably related to the kind of the sheath-core fiber: when the sheath-core fiber is preferably a composite polyester fiber, the drying temperature is preferably 90-110 ℃, and more preferably 95-105 ℃. In the invention, in order to avoid sticking of the wet paper web in the drying process, the temperatures of one-cylinder drying and two-cylinder drying need to be controlled, and the drying temperature and the drying rate are reasonably regulated, wherein the temperature of the one-cylinder drying is preferably 90-100 ℃, and the temperature of the two-cylinder drying is preferably 100-110 ℃. In the invention, when the sheath-core fiber is preferably an ES fiber, the drying temperature is preferably 100-130 ℃, more preferably 110-120 ℃, the drying preferably comprises one-cylinder drying and two-cylinder drying which are sequentially carried out, in order to avoid steel sticking, the temperatures of the one-cylinder drying and the two-cylinder drying need to be controlled, the temperature of the one-cylinder drying is preferably 100-120 ℃, and the temperature of the two-cylinder drying is preferably 120-130 ℃. In the invention, when the sheath-core fiber is preferably a mixture of the composite polyester fiber and the ES fiber, the drying temperature is preferably 100-120 ℃, the drying preferably comprises one-cylinder drying and two-cylinder drying which are sequentially carried out, the one-cylinder drying temperature is preferably 100-110 ℃, and the two-cylinder drying temperature is preferably 110-120 ℃. In the invention, the drying temperature is low, the sheath-core fiber is not melted, and the drying temperature is high, so that the fiber can be stuck to a cylinder.

After drying, the invention sequentially carries out coiling and slitting to obtain the mould pressing original sheet. The invention preferably performs slitting according to the molding size requirement.

After the mould pressing original sheets are obtained, a plurality of mould pressing original sheets are stacked together, and then mould pressing, preheating, heat preservation, pressure maintaining and cooling are sequentially carried out to obtain the skin-core fiber/carbon fiber thermoplastic composite material; the number of the plurality of mould pressing original sheets is 1-50.

In the invention, the pressure of the die pressing is preferably 0.5-10 MPa, and more preferably 2-6 MPa.

After the die pressing is finished, the invention carries out preheating treatment on the die-pressed product. In the present invention, the preheating temperature is preferably related to the type of the sheath-core fiber, and when the sheath-core fiber is preferably a composite polyester fiber, the preheating temperature is preferably 80 to 100 ℃, and more preferably 85 to 95 ℃. In the invention, when the sheath-core fiber is preferably the ES fiber, the preheating temperature is preferably 100-120 ℃, and more preferably 105-115 ℃. In the invention, when the sheath-core fiber is preferably a mixture of composite polyester fiber and ES fiber, the preheating temperature is preferably 90-110 ℃. In the invention, the preheating time is independent of the type of the sheath-core fiber, and the preheating time is preferably 5-20 min, more preferably 10-15 min.

After preheating is finished, the invention carries out heat preservation and pressure maintaining treatment on the preheated product. In the invention, the pressure for heat preservation and pressure maintaining is preferably 0.5-10 MPa, more preferably 1-8 MPa, and the pressure for heat preservation and pressure maintaining is independent of the type of the sheath-core fiber. In the invention, the temperature of the heat preservation and pressure maintaining is preferably related to the type of the sheath-core fiber, and when the sheath-core fiber is preferably a composite polyester fiber, the temperature of the heat preservation and pressure maintaining is preferably 160-240 ℃, and more preferably 180-210 ℃; when the sheath-core fiber is preferably an ES fiber, the temperature for heat preservation and pressure maintaining is preferably 120-150 ℃, and more preferably 130-140 ℃; when the sheath-core fiber is preferably a mixture of the composite polyester fiber and the ES fiber, the temperature for heat preservation and pressure maintaining is preferably 140-180 ℃, and more preferably 150-170 ℃. In the invention, the heat preservation and pressure maintaining time is independent of the type of the sheath-core fiber, and the heat preservation and pressure maintaining time is preferably 10-30 min, and more preferably 15-25 min.

In the preparation process, the skin layer of the skin-core fiber is firstly melted, so that the skin-core fiber and the carbon fiber are fully bonded, the prepreg in the traditional method can be replaced, and the method is simple.

The invention also provides the sheath-core fiber/carbon fiber thermoplastic composite material prepared by the preparation method in the technical scheme, and the thickness of the sheath-core fiber/carbon fiber thermoplastic composite material is preferably 1-15 mm. The sheath-core fiber and the carbon fiber in the sheath-core fiber/carbon fiber thermoplastic composite material provided by the invention can be uniformly mixed, so that the mechanical property of the composite material is effectively improved. The results of the examples show that the sheath-core fiber/carbon fiber thermoplastic composite material prepared by the invention has the bending strength of 250MPa, the tensile strength of 150MPa and the notch impact toughness of 80kJ/m²。

The technical solution of the present invention will be clearly and completely described below with reference to the embodiments of the present invention.