CN106948210B - A kind of method that foaming process prepares fibre reinforced composites - Google Patents

Abstract

The invention belongs to technical field of composite materials, disclose a kind of method that foaming process prepares fibre reinforced composites.The method is：Foaming agent is injected into foaming vessel to mix with fibrous suspension, then gas injection, impact or churned mechanically mode mixed foaming are used, generate foamed slurry of the volume concentration of gas phase between 55%~80%, online is manufactured paper with pulp molding, then using vacuumizing, eliminating lather collapse by the way of shower water or contact squeezing, individual layer paper is formed after drying, it is by certain grammes per square metre and thickness that multiple individual layer paper are compound, hot pressing or compression molding are carried out, obtains the fibre reinforced composites.The present invention substitutes water come bearing fiber using foam, reinforced phase fiber is made to be evenly distributed in the composite, enhancing effect is apparent.

Description

A method for preparing fiber-reinforced composite materials by foam forming method

technical field

The invention belongs to the technical field of composite materials, and in particular relates to a method for preparing fiber-reinforced composite materials by a foam forming method.

Background technique

Fiber-reinforced composite material is a new type of lightweight and high-strength material, which has good properties of corrosion resistance and excellent mechanical properties. With the development of lightweight in automotive, aerospace and other fields, the demand for fiber-reinforced composite materials in various industries is increasing and the requirements are getting higher and higher. In the forming process of composite materials, the requirements for water saving, energy saving, increasing economic benefits, and reducing pollution are also constantly increasing. There is an urgent need to use other fluids instead of water to disperse, transport fibers, and form paper sheets.

At present, fiber-reinforced composite materials have defects such as uneven distribution of reinforcing fibers and high energy consumption in forming methods, which greatly affect the production and application of materials.

Contents of the invention

In order to solve the above shortcomings and deficiencies of the prior art, the primary purpose of the present invention is to provide a method for preparing fiber-reinforced composite materials by foam forming.

Another object of the present invention is to provide a fiber reinforced composite material prepared by the above method.

The object of the invention is achieved through the following technical solutions:

A method for preparing fiber-reinforced composite materials by foam forming method, comprising the following preparation steps:

Inject the foaming agent into the foaming container to mix with the fiber suspension, and then use gas injection, impact or mechanical stirring to mix and foam to produce a foam slurry with a gas volume content between 55% and 80%, and copy it on the Internet. Type, and then vacuumize, spray water or contact press to eliminate the foam burst, and form a single-layer paper after drying, compound multiple single-layer papers according to a certain weight and thickness, and perform hot pressing or molding. The fiber reinforced composite material is obtained.

Preferably, the foaming agent is polyvinyl alcohol surfactant, sodium lauryl sulfate surfactant, fatty alcohol polyoxyethylene ether sodium sulfate surfactant, rosin soap surfactant, polyoxyethylene surface active agent At least one of active agents; the degree of alcoholysis of the polyvinyl alcohol surfactant is preferably 70% to 90%, and the viscosity is preferably 40 to 48mPa·s; the sodium lauryl sulfate surfactant The degree of alcoholysis is preferably 90% to 95%.

Preferably, the foaming agent is added in an amount of 0.1% to 10% of the mass of the foam slurry.

The fiber suspension includes reinforcement phase fibers and matrix phase fibers; the reinforcement phase fibers are preferably at least one of glass fibers, carbon fibers, plant fibers, nanocellulose fibers, ceramic fibers, metal fibers, and aramid fibers; The matrix phase fiber is preferably polyethylene fiber, polyethylene/polypropylene double melting point fiber, polypropylene fiber, polyacrylonitrile fiber, polyethylene terexylylene glycol ester fiber, polyvinyl chloride fiber, polylactic acid fiber, poly At least one of butylene terephthalate fibers; the mass ratio of reinforcing phase fibers to matrix phase fibers is (1-5):(95-99).

Preferably, the gas injection refers to injecting air, nitrogen or carbon dioxide gas.

Preferably, the total fiber content of the foam slurry is 0.01%-5wt.%, and the foam diameter is 50-400 μm.

Preferably, the vacuum degree of the vacuuming ranges from 10 ^-5 to 10 ⁵ Pa, more preferably from 10 ² to 10 ⁵ Pa; the pressure of the spray water is from 1.5×10 ⁵ to 3×10 ⁵ Pa, More preferably, it is 1.8×10 ⁵ to 2.5×10 ⁵ Pa; the pressing pressure of the contact pressing is 1×10 ⁵ to 2×10 ⁵ Pa, more preferably 1.3×10 ⁵ to 1.5×10 ⁵ Pa.

Preferably, the drying refers to drying until the dryness of the paper is 10%-80%, more preferably 40%-50%.

Preferably, the specific gram weight and thickness refer to a gram weight of 50-3000 g/m ² and a thickness of 1-100 mm; more preferably a gram weight of 100-200 g/m ² and a thickness of 2-20 mm.

Preferably, the temperature of the hot pressing or mold pressing is 130-200° C., and the time is 0.5-30 minutes; more preferably, the temperature is 175-185° C., and the time is 2-10 minutes.

A fiber-reinforced composite material is prepared by the above method.

The preparation method of the present invention and the resulting product have the following advantages and beneficial effects:

(1) The present invention adopts the foam forming method to make composite technology, and replaces water with foam to carry fibers, so that the reinforcement phase fibers are evenly distributed in the composite material, and the reinforcement effect is improved;

(2) In the present invention, nanocellulose fibers can be used as one of the reinforcing phases, which improves the interfacial compatibility of the composite material.

Description of drawings

Fig. 1 is the structural representation of the inclined wire paper machine used in the embodiment of the present invention 13;

Figure 2 is a working principle diagram of the contact press defoaming device used in Example 13 of the present invention;

Fig. 3 is a schematic flow chart of the hot-pressing treatment in Example 13 of the present invention.

Detailed ways

The present invention will be further described in detail below in conjunction with examples, but the embodiments of the present invention are not limited thereto.

Example 1

(1) Dilute polyvinyl alcohol surfactant (alcoholysis degree is 80%, viscosity is 45mPa·s) with a small amount of water to make foaming agent solution A; dilute polyethylene fiber with water to obtain slurry B; Nanocellulose fibers are mixed and diluted with water to obtain slurry C; the three solutions A, B, and C are mixed together in the slurry tank, and stirred by high-speed machinery to obtain a gas volume content of 55% and a total fiber content of 1wt.%. 1. Foam slurry with a foam diameter of 50-400 μm; wherein the net content of polyvinyl alcohol surfactant added is 1% of the mass of the foam slurry, and the ratio of the net content of polyethylene fibers to nanocellulose fibers is 99:1.

(2) The prepared foam slurry is formed by a circular wire paper machine at one time, and then vacuumized under the condition of a vacuum of 10 ² Pa to eliminate the foam rupture, and then dried to a dryness of 40% to obtain a single-layer paper sheet ;

(3) Composite a plurality of single-layer paper sheets according to the paper basis weight of 200 g/m ² , and heat press at 175-185° C. for 5 minutes to obtain the fiber-reinforced composite material.

Example 2

The preparation method is the same as in Example 1, except that the foaming agent adopts a sodium lauryl sulfate surfactant with a degree of alcoholysis of 90%, the ratio of the net content of polyethylene fibers to nanocellulose fibers is 98:2, and the rest The conditions are exactly the same.

Example 3

The preparation method is the same as in Example 1, except that the foaming agent uses fatty alcohol polyoxyethylene ether sodium sulfate surfactant, the ratio of the net content of polyethylene fibers to nanocellulose fibers is 97:3, and the rest of the conditions are identical.

Example 4

The preparation method is the same as in Example 1, except that the foaming agent is a rosin soap surfactant, the ratio of the net content of polyethylene fibers to nanocellulose fibers is 96:4, and the rest of the conditions are identical.

Example 5

The preparation method is the same as in Example 1, except that the foaming agent uses polyoxyethylene surfactant, the ratio of the net content of polyethylene fibers to nanocellulose fibers is 95:5, and the rest of the conditions are identical.

Example 6

The preparation method is the same as in Example 1, except that the foaming agent adopts polyvinyl alcohol+sodium lauryl sulfate mixed surfactant, the ratio of the net content of polyethylene fibers to nanocellulose fibers is 95:5, and the remaining conditions are complete. same.

Table 1 shows the performance test data of the nanocellulose fiber-reinforced composite materials prepared in Examples 1-6.

Table 1

As can be seen from the results in Table 1, the thickness of the nanocellulose fiber-reinforced composite material prepared in Examples 1 to 6 of the present invention is between 1.9 and 2.1 mm, the tensile strength is between 39.6 and 48.0 MPa, and the bending strength is between 89.7 and 48.0 MPa. Between 95.7MPa, impact strength between 14.7～20.6KJ m ^-2 , water absorption between 0.1%～0.3%, resistivity between 48000～53200×10 ⁶ Ω·cm. All performance indexes are better than or equal to commercially available polyethylene plastic sheets.

Example 7

(1) Dilute polyvinyl alcohol surfactant (alcoholysis degree is 70%, viscosity is 40mPa·s) with a small amount of water to make foaming agent solution A; dilute polyethylene fiber with water to obtain slurry B; Mix and dilute glass fiber with water to obtain slurry C; mix the three solutions A, B, and C in the slurry tank, and inject air with an air injection device to obtain a gas volume content of 60% and a total fiber content of 2%. Foam slurry with a foam diameter of 50-400 μm; the net content of polyvinyl alcohol surfactant added is 2% of the mass of the foam slurry, and the net content ratio of polyethylene fiber to glass fiber is 99:1.

(2) The prepared foam slurry is formed by one-time papermaking with an inclined wire paper machine, and then the foam is broken and eliminated under the condition of spray water pressure of 2.0×10 ⁵ Pa, and then dried to a dryness of 45% to obtain a single layer paper;

(3) Composite a plurality of single-layer paper sheets according to the paper basis weight of 200 g/m ² , and heat press at 175-185° C. for 5 minutes to obtain the fiber-reinforced composite material.

Example 8

The preparation method is the same as in Example 7, except that the foaming agent adopts a sodium lauryl sulfate surfactant with a degree of alcoholysis of 90%, the ratio of the net content of polyethylene fibers to glass fibers is 98:2, and the remaining conditions are complete. same.

Example 9

The preparation method is the same as in Example 7, except that the foaming agent uses fatty alcohol polyoxyethylene ether sodium sulfate surfactant, the ratio of the net content of polyethylene fiber to glass fiber is 97:3, and the rest of the conditions are identical.

Example 10

The preparation method is the same as in Example 7, except that the foaming agent is a rosin soap surfactant, the ratio of the net content of polyethylene fiber to glass fiber is 96:4, and the rest of the conditions are identical.

Example 11

The preparation method is the same as in Example 7, except that the foaming agent uses polyoxyethylene surfactant, the ratio of the net content of polyethylene fiber to glass fiber is 95:5, and the rest of the conditions are identical.

Example 12

The preparation method is the same as that of Example 7, except that the foaming agent is polyvinyl alcohol + sodium lauryl sulfate mixed surfactant, the ratio of the net content of polyethylene fiber to glass fiber is 95:5, and the rest of the conditions are identical.

The performance test data of the glass fiber reinforced composite materials prepared in Examples 7-12 are shown in Table 2.

Table 2

It can be seen from Table 2 that the thickness of the glass fiber reinforced composite materials prepared in Examples 7 to 12 of the present invention is between 1.9 and 2.1 mm, the tensile strength is between 30.5 and 35.9 MPa, and the bending strength is between 74.3 and 80.6 MPa. The impact strength is between 8.8 and 9.6KJ m ^-2 , the water absorption is between 0.1% and 0.9%, and the resistivity is between 49000-53000×10 ⁶ Ω·cm. All performance indexes are better than or equal to commercially available polyethylene plastic sheets.

Example 13

(1) Dilute polyvinyl alcohol surfactant (alcoholysis degree is 90%, viscosity is 48mPa·s) with a small amount of water to make foaming agent solution A; dilute polyethylene fiber with water to obtain slurry B; Mix and dilute the ceramic fiber with water to obtain slurry C; mix the three solutions A, B, and C in the slurry tank, and inject air with the gas injection device to obtain a gas volume content of 70% and a total fiber content of 3%. Foam slurry with a foam diameter of 50-400 μm; the net content of polyvinyl alcohol surfactant added is 3% of the mass of the foam slurry, and the ratio of the net content of polyethylene fiber to ceramic fiber is 99:1.

(2) The prepared foam slurry is formed by the inclined wire paper machine shown in Figure 1 once (the foam slurry is formed by the pulp distributor, forming net and dehydration original of the inclined wire paper machine successively), and then by contact The press defoaming device (the working principle diagram is shown in Figure 2), under the condition that the press pressure P is 1.4×10 ⁵ Pa, the foam is broken and eliminated, and then dried to a dryness of 50% to obtain a single-layer paper sheet;

(3) According to the sheet weight of 200g/m ² , multiple single-layer paper sheets are combined, and heat-pressed at 175-185°C in the mold for 5 minutes (the schematic diagram of the heat-pressing process is shown in Figure 3, and P represents hot-pressing pressure), to obtain the fiber-reinforced composite material.

Example 14

The preparation method is the same as in Example 13, except that the foaming agent adopts a sodium lauryl sulfate surfactant with a degree of alcoholysis of 90%, the ratio of the net content of polyethylene fibers to ceramic fibers is 98:2, and the remaining conditions are complete. same.

Example 15

The preparation method is the same as that of Example 13, except that the foaming agent uses fatty alcohol polyoxyethylene ether sodium sulfate surfactant, the ratio of the net content of polyethylene fiber to ceramic fiber is 97:3, and the rest of the conditions are identical.

Example 16

The preparation method is the same as in Example 13, except that the foaming agent is rosin soap surfactant, the ratio of the net content of polyethylene fiber to ceramic fiber is 96:4, and the rest of the conditions are identical.

Example 17

The preparation method is the same as that of Example 13, except that the foaming agent uses polyoxyethylene surfactant, the ratio of the net content of polyethylene fiber to ceramic fiber is 95:5, and the rest of the conditions are identical.

Example 18

The preparation method is the same as in Example 13, except that the foaming agent is polyvinyl alcohol + sodium lauryl sulfate mixed surfactant, the ratio of the net content of polyethylene fiber to ceramic fiber is 95:5, and the rest of the conditions are exactly the same.

The performance test data of the ceramic fiber reinforced composite materials prepared in Examples 13-18 are shown in Table 3.

table 3

It can be seen from the results in Table 3 that the thickness of the ceramic fiber reinforced composite materials prepared in Examples 13 to 18 of the present invention is between 1.9 and 2.1 mm, the tensile strength is between 35.1 and 38.8 MPa, and the bending strength is between 68.1 and 75.6 MPa The impact strength is between 8.4 and 9.2KJ m ^-2 , the water absorption is between 0.4% and 0.8%, and the resistivity is between 49500 and 58200×10 ⁶ Ω·cm. All performance indexes are better than or equal to commercially available polyethylene plastic sheets.

Example 19

(1) Dilute polyvinyl alcohol surfactant (alcoholysis degree is 80%, viscosity is 45mPa·s) with a small amount of water to make foaming agent solution A; dilute polyethylene fiber with water to obtain slurry B; Metal fibers are mixed and diluted with water to obtain slurry C; the three solutions A, B, and C are mixed together in the slurry tank, and a hydraulic impact device is used to make bubbles to obtain a gas volume content of 80%, a total fiber content of 4%, and Foam slurry with a foam diameter of 50-400 μm; the net content of polyvinyl alcohol surfactant added is 4% of the mass of the foam slurry, and the ratio of the net content of polyethylene fibers to metal fibers is 99:1.

(2) The prepared foam slurry is formed by one-time papermaking with an inclined wire paper machine, and then vacuumized under the condition of a vacuum of 10 ³ Pa to eliminate foam rupture, and then dried to a dryness of 45% to obtain a single-layer paper sheet ;

(3) Composite a plurality of single-layer paper sheets according to the paper basis weight of 200 g/m ² , and heat press at 175-185° C. for 5 minutes to obtain the fiber-reinforced composite material.

Example 20

The preparation method is the same as in Example 19, except that the foaming agent adopts a sodium lauryl sulfate surfactant with a degree of alcoholysis of 95%, the ratio of the net content of polyethylene fibers to metal fibers is 98:2, and the remaining conditions are complete. same.

Example 21

The preparation method is the same as in Example 19, except that the foaming agent uses fatty alcohol polyoxyethylene ether sodium sulfate surfactant, the ratio of the net content of polyethylene fibers to metal fibers is 97:3, and the rest of the conditions are identical.

Example 22

The preparation method is the same as in Example 19, except that the foaming agent is a rosin soap surfactant, the ratio of the net content of polyethylene fibers to metal fibers is 96:4, and the rest of the conditions are identical.

Example 23

The preparation method is the same as that of Example 19, except that the foaming agent uses polyoxyethylene surfactant, the ratio of the net content of polyethylene fibers to metal fibers is 95:5, and the rest of the conditions are identical.

Example 24

The preparation method is the same as that in Example 19, except that the foaming agent is a mixed surfactant of polyvinyl alcohol + sodium lauryl sulfate, the ratio of the net content of polyethylene fibers to metal fibers is 95:5, and the rest of the conditions are exactly the same.

The performance test data of the metal fiber reinforced composite materials prepared in Examples 19-24 are shown in Table 4.

Table 4

It can be seen from the results in Table 4 that the thickness of the metal fiber reinforced composite materials prepared in Examples 19 to 24 of the present invention is between 1.9 and 2.1 mm, the tensile strength is between 25.8 and 29.3 MPa, and the bending strength is between 69.8 and 75.6 MPa The impact strength is between 7.0 and 7.8KJ m ^-2 , the water absorption is between 0.4% and 0.7%, and the resistivity is between 0.33 and 58000×10 ⁶ Ω·cm. All performance indexes are better than or equal to commercially available polyethylene plastic sheets.

Example 25

(1) Dilute polyvinyl alcohol surfactant (alcoholysis degree is 80%, viscosity is 45mPa·s) with a small amount of water to make foaming agent solution A; dilute polyethylene fiber with water to obtain slurry B; Carbon fiber is mixed and diluted with water to obtain slurry C; the three solutions A, B, and C are mixed together in the slurry tank, and a hydraulic impact device is used to make foam to obtain a foam with a volume content of 70% and a total fiber content of 5%. Foam slurry with a diameter of 50-400 μm; the net content of polyvinyl alcohol surfactant added is 10% of the mass of the foam slurry, and the ratio of the net content of polyethylene fiber to carbon fiber is 99:1.

(2) The prepared foam slurry is formed by one-time papermaking with an inclined wire paper machine, and then vacuumized under the condition of a vacuum of 10 ⁴ Pa to eliminate foam rupture, and then dried to a dryness of 45% to obtain a single-layer paper sheet ;

(3) Composite a plurality of single-layer paper sheets according to the paper basis weight of 200 g/m ² , and heat press at 175-185° C. for 5 minutes to obtain the fiber-reinforced composite material.

Example 26

The preparation method is the same as in Example 25, except that the foaming agent adopts a sodium lauryl sulfate surfactant with a degree of alcoholysis of 95%, the ratio of the net content of polyethylene fibers to carbon fibers is 98:2, and the rest of the conditions are exactly the same .

Example 27

The preparation method is the same as that of Example 25, except that the foaming agent uses fatty alcohol polyoxyethylene ether sodium sulfate surfactant, the ratio of the net content of polyethylene fiber to carbon fiber is 97:3, and the rest of the conditions are identical.

Example 28

The preparation method is the same as that of Example 25, except that the foaming agent is a rosin soap surfactant, the ratio of the net content of polyethylene fibers to carbon fibers is 96:4, and the rest of the conditions are identical.

Example 29

The preparation method is the same as that of Example 25, except that the foaming agent uses polyoxyethylene surfactant, the ratio of the net content of polyethylene fibers to carbon fibers is 95:5, and the rest of the conditions are identical.

Example 30

The preparation method is the same as in Example 25, except that the foaming agent is a mixed surfactant of polyvinyl alcohol + sodium lauryl sulfate, the ratio of the net content of polyethylene fibers to carbon fibers is 95:5, and the rest of the conditions are identical.

The performance test data of the carbon fiber reinforced composite materials prepared in Examples 25-30 are shown in Table 5.

table 5

It can be seen from the results in Table 5 that the thickness of the carbon fiber reinforced composite materials prepared in Examples 25-30 of the present invention is between 1.9-2.1mm, the tensile strength is between 27.4-29.1MPa, and the bending strength is between 64.5-66.3MPa The impact strength is between 6.8 and 7.4KJ m ^-2 , the water absorption is between 0.3% and 0.8%, and the resistivity is between 0.19 and 44000×10 ⁶ Ω·cm. All performance indexes are better than or equal to commercially available polyethylene plastic sheets.

The above-mentioned embodiment is a preferred embodiment of the present invention, but the embodiment of the present invention is not limited by the above-mentioned embodiment, and any other changes, modifications, substitutions, combinations, Simplifications should be equivalent replacement methods, and all are included in the protection scope of the present invention.

Claims (8)

1. A method for preparing fiber-reinforced composites by foam forming, characterized in that it comprises the following preparation steps: Inject the foaming agent into the foaming container to mix with the fiber suspension, and then use gas injection, impact or mechanical stirring to mix and foam to produce a foam slurry with a gas volume content between 55% and 80%, and copy it on the Internet. Type, and then use vacuum, spray water or contact pressing to eliminate the foam burst, and form a single-layer paper after drying, compound multiple single-layer paper according to a certain weight and thickness, and perform hot pressing or molding. obtaining the fiber-reinforced composite material; The fiber suspension includes reinforcement phase fibers and matrix phase fibers; the reinforcement phase fibers refer to at least one of glass fibers, carbon fibers, plant fibers, nanocellulose fibers, ceramic fibers, metal fibers, and aramid fibers The matrix phase fiber refers to polyethylene fiber, polyethylene/polypropylene double melting point fiber, polypropylene fiber, polyacrylonitrile fiber, polyethylene terephthalate fiber, polyvinyl chloride fiber, polylactic acid fiber 1. At least one of polybutylene terephthalate fibers; the mass ratio of reinforcing phase fibers to matrix phase fibers is (1～5):(95～99); The total fiber content of the foam slurry is 0.01%-5wt.%, and the foam diameter is 50-400 μm. 2. a kind of foam forming method according to claim 1 prepares the method for fiber-reinforced composite material, is characterized in that: described blowing agent is polyvinyl alcohol surfactant, sodium lauryl sulfate surfactant, At least one of fatty alcohol polyoxyethylene ether sodium sulfate surfactant, rosin soap surfactant, and polyoxyethylene surfactant; the degree of alcoholysis of the polyvinyl alcohol surfactant is 70% to 90%, The viscosity is 40-48mPa·s; the degree of alcoholysis of the sodium lauryl sulfate surfactant is 90%-95%. 3. A method for preparing fiber-reinforced composite materials by a foam forming method according to claim 1, characterized in that: the amount of the foaming agent added is 0.1% to 10% of the mass of the foam slurry. 4. A method for preparing fiber-reinforced composite materials by foam forming method according to claim 1, characterized in that: the gas injection refers to the injection of air, nitrogen or carbon dioxide gas. 5. A method for preparing fiber-reinforced composite materials by foam forming method according to claim 1, characterized in that: the vacuum degree of said vacuuming ranges from 10 ⁻⁵ to 10 ⁵ Pa; The pressure is 1.5×10 ⁵ ~3×10 ⁵ Pa; the pressing pressure of the contact pressing is 1×10 ⁵ ~2×10 ⁵ Pa. 6. A method for preparing fiber-reinforced composite materials by foam forming method according to claim 1, characterized in that: said drying refers to drying until the dryness of the paper is 10%-80%. 7. A method for preparing fiber-reinforced composite materials by foam forming method according to claim 1, characterized in that: said according to a certain grammage and thickness means that the grammage is 50-3000g/m ² and the thickness is 1 ~100mm; the temperature of the hot pressing or mold pressing is 130~200°C, and the time is 0.5~30min. 8. A fiber-reinforced composite material, characterized in that it is prepared by the method according to any one of claims 1-7.