Preparation method of high-modulus recycled fiber blended yarn and application of high-modulus recycled fiber blended yarn in pultrusion process

Abstract

The invention discloses a preparation method of high-modulus recycled fiber blended yarns, which comprises the following steps of: obtaining recycled fibers from a scrapped composite material, treating short fibers of the fibers, carding and blending the short fibers and thermoplastic fibers such as nylon through a spinning machine to obtain slivers or gauzes, and drawing through a drawing frame to enable the slivers to be uniform, so as to obtain the high-modulus recycled fiber blended yarns. According to the method, the processing modes of opening, carding, drawing and spinning are adopted, the orientation degree, the uniformity, the rigidity and the strength of yarn fibers are improved, and the recycling value of the recycled fibers is increased. The blended yarn can replace bulked yarn in the pultrusion process, the effects of reducing cost and improving toughness are achieved, the structural designability is improved, the application value is improved, and the same effect as new yarn is achieved.

Description

Technical Field

[0001] The invention relates to the field of manufacturing, processing and treatment methods of nonwoven fabrics, and in particular to a preparation method of high modulus recycled fiber blended yarn and an application thereof in a pultrusion process. Background Art

[0002] Fibers have the characteristics of high strength and corrosion resistance and are important reinforcing materials. However, the production of fibers consumes a lot of energy, and fiber-reinforced materials in many composite materials are not easy to degrade. If fiber-reinforced materials are recycled and reused, energy consumption can be reduced and costs can be cut. However, the reuse value of existing reinforcing fibers after recycling is not high, and re-production cannot achieve the effect of original fibers. Therefore, it is crucial to develop a preparation method for recycled fibers with high modulus and high strength.

[0003] Chinese invention patent CN112877817A discloses a recyclable and environmentally friendly hemp-cotton fabric recycling fiberization and reproduction process, which undergoes fiberization treatments such as sorting of waste fabrics, washing and cleaning, desizing, washing and desizing, sterilization, washing and drying, and crushing. Mild treatment processes are used in the process to prevent secondary pollution to the environment, making the entire fiberization process more environmentally friendly. However, the strength and modulus of the recycled fibers obtained are not good, and the performance of the original fibers cannot be achieved when reused. Chinese invention patent CN118756431A discloses a high-fiber content, high-orientation recycled fiber reinforced composite material and its preparation method, which effectively reduces the molding difficulty of thermoplastic resin fiber-based composite materials through the steps of opening, mixing, combing, and blending, thereby providing a composite material molding idea for some high-viscosity, difficult-to-form thermoplastic resin fibers. However, the strength of the recycled fibers obtained is not high, and the effect of the original fibers cannot be achieved. Summary of the invention

[0004] In order to develop a method for preparing recycled fibers with high modulus and high strength effects, the present invention obtains recycled fibers from scrapped composite materials, processes the fiber staple fibers, and then combs and blends them with thermoplastic fibers such as nylon through a spinning machine to obtain yarns or yarn nets, then draws the yarns through a drawing machine to make the yarns uniform, and finally twists and spins them into yarns of specific fineness through a spinning machine, thereby giving the yarns the characteristics of high modulus.

[0005] A first aspect of the present invention provides a method for preparing a high modulus recycled fiber blended yarn, comprising the following steps:

[0006] S1 degrades and recycles waste composite materials to obtain recycled reinforcing fibers;

[0007] S2 removes the residual resin on the surface of the recycled reinforcing fiber, and then mixes and loosens the fiber with the thermoplastic resin fiber. The opened fiber mixture passes through a carding machine to obtain a mixed yarn.

[0008] S3 draws the mixed yarn through a drawing frame;

[0009] After S4 drawing, the yarn is twisted through a spinning machine to form a yarn, and the outermost layer of the yarn is wrapped with filaments to obtain a blended yarn.

[0010] As a preferred embodiment, the length of the recycled reinforcement fiber is 40-200 mm.

[0011] As a preferred embodiment, the type of the recycled reinforcing fiber is selected from at least one of glass fiber, carbon fiber, basalt fiber and boron fiber.

[0012] As a preferred embodiment, the mass proportion of the recycled reinforcing fibers in the fiber mixture is 1-100%, excluding endpoint values.

[0013] As a preferred embodiment, the mass ratio of the recycled reinforcing fiber to the thermoplastic resin fiber is (1-3):1.

[0014] As a preferred embodiment, the thermoplastic resin fiber is selected from at least one of nylon, polyester fiber, polypropylene fiber, polyetheretherketone fiber, and polyphenylene sulfide fiber.

[0015] As a preferred embodiment, the number of opening times in step S2 is 1-5 times, and the gram weight of the mixed yarn is 3-7 g / m.

[0016] As a preferred embodiment, the drawing times in step S3 is 1-3 times, the weight of the blended yarn finally obtained in step S4 is 0.3-0.7 g / m, and the yarn density is 1-5 g / cm 3 .

[0017] The high modulus recycled fiber obtained by mixing, twisting and drawing short fibers and thermoplastic fibers in a certain proportion can give the yarn the characteristics of high modulus and high orientation, and the recycled yarn has high utilization value and can achieve the function of the original yarn. The possible reasons are: the mixed opening of the recycled short fiber mixture and the thermoplastic fiber can improve the mixing uniformity of the recycled short fiber and the thermoplastic fiber, and the mixing of short fibers and thermoplastic fibers can improve the toughness of the recycled short fibers, reduce the rigidity of the fibers, and avoid the breakage of the yarn.

[0018] The inventor twisted and stretched the mixed fibers to improve the strength of the yarn, making it reach the strength of the original fibers and improving the utilization value of the regenerated yarn. Compared with the traditional method of directly adding high-modulus fibers to improve performance, the addition of thermoplastic fibers can give it certain pultrusion properties, and the prepared extruded board has no obvious difference from the board made of original fibers.

[0019] The second aspect of the present invention provides an application of a method for preparing a high modulus recycled fiber blended yarn, and the prepared blended yarn is applied to a pultrusion process.

[0020] As a preferred embodiment, the pultrusion process includes a yarn frame and yarn guide, resin impregnation, preforming, mold heating and curing, demoulding post-processing and cutting.

[0021] The yarn rack is used for yarn collection, and the yarn collection forms are divided into inner yarn collection and outer yarn collection, the inner yarn collection is glass fiber, and the outer yarn collection is carbon fiber. There are two yarn racks, and the two yarn racks are arranged front and back, side by side in sequence, and the straightness is easy to control. When two yarn racks are used, the distance between the two yarn racks needs to be extended to the distance of the rubber groove, and the distance from the yarn rack to the rubber groove is 4-6 meters, and the yarn entry angle of the rubber groove is small.

[0022] As a preferred embodiment, the yarn threading holes in the yarn guiding process can be made of porcelain eyes or PP eyes. The porcelain eyes are chamfered, and the surface of the porcelain eyes is smoother and less likely to scratch the yarn. Use a PP yarn collecting plate to punch holes, polish the inside to be smooth, and chamfer the edges. To prevent the yarn from falling due to gravity, pre-form the yarn in advance, gather the yarn, and converge the angle. The yarn is concentrated, and a yarn splitter is used to disperse it into small strands when feeding the yarn. More strands of yarn are passed through each hole, which can reduce the pulling and extrusion resistance and facilitate the control of straightness.

[0023] As a preferred embodiment, the resin is infiltrated with a stirrer at 300 rpm for 15 minutes. The resin is prepared for 3 hours at a time and added in batches every hour. When adding, the resin in the glue tank is stirred evenly with a board to prevent the old resin from agglomerating. Try not to touch the yarn when scraping the glue. The glue tank is designed with glue pressing, which is conducive to increasing the infiltration effect, reducing dead corners, avoiding resin residue, accelerating the circulation of resin, and facilitating replacement and cleaning. After the fiber is pulled out of the glue tank, release cloth can be added to the upper and lower surfaces of the fiber as needed.

[0024] As a preferred embodiment, the excess resin is removed and returned to the resin tank during the preforming process to reduce the friction between the fiber bundle and the hardening die and the excess resin. The fiber bundle, bulked yarn, or other reinforcing materials are given an appropriate position to enter the curing stage. The preforming bundling process needs to be completed by a preforming die.

[0025] As a preferred embodiment, the ratio of the cross-sectional area of ​​the molding mold to the cross-sectional area of ​​the product during the heating and curing process of the mold is ≥10 to ensure that the mold has sufficient strength and rigidity, and the heat distribution after heating is uniform and stable. The length of the pultrusion die is determined according to the traction speed and the resin curing speed during the molding process to ensure that the demolding and curing degree is reached when the product is pulled out. The inner surface is chrome-plated or nitrided, and the surface of the mold cavity is smooth and wear-resistant, which increases the service life of the mold. The mold temperature is higher than the exothermic peak of the resin, and is divided into three stages of heating. The temperature difference of the three stages is controlled at 20-30°C, so that the release point is located at 55-60% of the mold length.

[0026] The third aspect of the present invention provides a recycled fiber reinforced composite material, which is prepared by the above-mentioned pultrusion process.

[0027] Compared with the prior art, the present invention has the following beneficial effects:

[0028] (1) In the method for preparing high modulus recycled fiber blended yarn of the present invention, the thermoplastic resin fiber improves the toughness and flexibility of the blended yarn, optimizes the pultrusion process, and broadens the application of recycled fibers in the pultrusion process.

[0029] (2) The method for preparing the high modulus recycled fiber blended yarn of the present invention adopts the processing methods of opening, carding, drawing and spinning, which improves the orientation, uniformity, stiffness and strength of the yarn fibers and enhances the reuse value of the recycled fibers.

[0030] (3) The preparation method of the high modulus recycled fiber blended yarn described in the present invention uses fibers with a length of 40-200 mm and then matches them with thermoplastic resin fibers of the same length to ensure that the fibers are evenly mixed and have consistent lengths after opening. The opening method of the opening machine is gentle, which reduces fiber breakage and stiffness loss.

[0031] (4) The preparation method of the high modulus recycled fiber blended yarn described in the present invention adopts a drawing machine to draw the yarn and then twist it, which can further improve the uniformity and orientation of the yarn, increase the cohesion between the fibers and the yarn tension, thereby obtaining a yarn with a finer fineness, further improving the yarn performance.

[0032] (5) The recycled fiber obtained by the preparation method of the high modulus recycled fiber blended yarn described in the present invention can replace the bulked yarn in the pultrusion process, achieve the effect of reducing cost and improving toughness, improve the design of the structure, enhance the application value, and achieve the same effect as the new yarn. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 The blended yarns prepared in Examples 1 and 5 of the present application, the left picture is the blended yarn of Example 1, and the right picture is the blended yarn of Example 5.

[0034] Figure 2 It is bulked yarn.

[0035] Figure 3 It is the creel in the pultrusion process.

[0036] Figure 4 Schematic diagram of the pultrusion process. DETAILED DESCRIPTION

[0037] Example 1

[0038] A method for preparing high modulus recycled fiber blended yarn comprises the following steps:

[0039] S1 degrades and recycles waste composite materials to obtain recycled reinforcing fibers;

[0040] S2 removes the residual resin on the surface of the recycled reinforcing fiber, and then mixes and loosens the fiber with the thermoplastic resin fiber. The opened fiber mixture passes through a carding machine to obtain a mixed yarn.

[0041] S3 draws the mixed yarn through a drawing frame;

[0042] After S4 drawing, the yarn is twisted through a spinning machine to form a yarn, and the outermost layer of the yarn is wrapped with filaments to obtain a blended yarn.

[0043] The length of the recycled reinforcement fiber is 80 mm; the length of the thermoplastic resin fiber is 88 mm.

[0044] The recycled reinforcing fiber is glass fiber, and the thermoplastic resin fiber is nylon 56. The mass ratio of the recycled reinforcing fiber to the thermoplastic resin fiber is 3:1.

[0045] The cylinder in the carding machine combs the fiber mixture at a speed of 25 r / min.

[0046] The number of opening times in step S2 is 3 times, and the gram weight of the mixed yarn is 4.87 g / m.

[0047] The drawing times in step S3 are 2 times, and the blended yarn finally obtained in step S4 has a gram weight of 0.4749 g / m and a yarn density of 2.22 g / cm 3 .

[0048] The blended yarns were unidirectionally laid and then compression molded at 260°C to evaluate the mechanical properties.

[0049] Example 2

[0050] A method for preparing high modulus recycled fiber blended yarn comprises the following steps:

[0051] S1 degrades and recycles waste composite materials to obtain recycled reinforcing fibers;

[0052] S2 removes the residual resin on the surface of the recycled reinforcing fiber, and then mixes it with the thermoplastic resin fiber. The fiber mixture passes through a carding machine to obtain a mixed yarn;

[0053] S3 draws the mixed yarn through a drawing frame;

[0054] After S4 drawing, the yarn is twisted through a spinning machine to form a yarn, and the outermost layer of the yarn is wrapped with filaments to obtain a blended yarn.

[0055] The length of the recycled reinforcement fiber is 80 mm; the length of the thermoplastic resin fiber is 88 mm.

[0056] The recycled reinforcing fiber is glass fiber, and the thermoplastic resin fiber is nylon 56. The mass ratio of the recycled reinforcing fiber to the thermoplastic resin fiber is 3:1.

[0057] The cylinder in the carding machine combs the fiber mixture at a speed of 25 r / min.

[0058] The drawing times in step S3 are 2 times, and the blended yarn finally obtained in step S4 has a gram weight of 0.4749 g / m and a yarn density of 2.22 g / cm 3 .

[0059] The blended yarns were unidirectionally laid and then compression molded at 260°C to evaluate the mechanical properties.

[0060] Example 3

[0061] A method for preparing high modulus recycled fiber blended yarn comprises the following steps:

[0062] S1 degrades and recycles waste composite materials to obtain recycled reinforcing fibers;

[0063] S2 removes the residual resin on the surface of the recycled reinforcing fiber, and then mixes and loosens the fiber with the thermoplastic resin fiber. The opened fiber mixture passes through a carding machine to obtain a mixed yarn.

[0064] S3 twists the mixed yarn through a spinning machine to form yarn, and wraps the outermost layer of the yarn with filaments to obtain a blended yarn.

[0065] The length of the recycled reinforcement fiber is 80 mm; the length of the thermoplastic resin fiber is 88 mm.

[0066] The recycled reinforcing fiber is glass fiber, and the thermoplastic resin fiber is nylon 56. The mass ratio of the recycled reinforcing fiber to the thermoplastic resin fiber is 3:1.

[0067] The cylinder in the carding machine combs the fiber mixture at a speed of 25 r / min.

[0068] The number of opening times in step S2 is 3 times, and the gram weight of the mixed yarn is 4.87 g / m.

[0069] The blended yarn finally obtained in step S4 has a gram weight of 0.4749 g / m and a yarn density of 2.22 g / cm 3 .

[0070] The blended yarns were unidirectionally laid and then compression molded at 260°C to evaluate the mechanical properties.

[0071] Example 4

[0072] A method for preparing high modulus recycled fiber blended yarn comprises the following steps:

[0073] S1 degrades and recycles waste composite materials to obtain recycled reinforcing fibers;

[0074] S2 removes the residual resin on the surface of the recycled reinforcing fiber, and then mixes and loosens the fiber with the thermoplastic resin fiber. The opened fiber mixture passes through a carding machine to obtain a mixed yarn.

[0075] S3 draws the mixed yarn through a drawing frame;

[0076] S4 obtains the blended yarn.

[0077] The length of the recycled reinforcement fiber is 80 mm; the length of the thermoplastic resin fiber is 88 mm.

[0078] The recycled reinforcing fiber is glass fiber, and the thermoplastic resin fiber is nylon 56. The mass ratio of the recycled reinforcing fiber to the thermoplastic resin fiber is 3:1.

[0079] The cylinder in the carding machine combs the fiber mixture at a speed of 25 r / min.

[0080] The number of opening times in step S2 is 3 times, and the gram weight of the mixed yarn is 4.87 g / m.

[0081] The blended yarn finally obtained in step S4 has a gram weight of 0.4749 g / m and a yarn density of 2.22 g / cm 3 .

[0082] The blended yarns were unidirectionally laid and then compression molded at 260°C to evaluate the mechanical properties.

[0083] Example 5

[0084] A method for preparing high modulus recycled fiber blended yarn comprises the following steps:

[0085] S1 degrades and recycles waste composite materials to obtain recycled reinforcing fibers;

[0086] S2 removes the residual resin on the surface of the recycled reinforcing fiber, and then mixes and loosens the fiber with the thermoplastic resin fiber. The opened fiber mixture passes through a carding machine to obtain a mixed yarn.

[0087] S3 draws the mixed yarn through a drawing frame;

[0088] After S4 drawing, the yarn is twisted through a spinning machine to form a yarn, and the outermost layer of the yarn is wrapped with filaments to obtain a blended yarn.

[0089] The length of the recycled reinforcement fiber is 80 mm; the length of the thermoplastic resin fiber is 80 mm.

[0090] The recycled reinforcing fiber is glass fiber, the thermoplastic resin fiber is polyphenylene sulfide fiber, and the mass ratio of the recycled reinforcing fiber to the thermoplastic resin fiber is 3:1.

[0091] The cylinder in the carding machine combs the fiber mixture at a speed of 25 r / min.

[0092] The number of opening times in step S2 is 3 times, and the gram weight of the mixed yarn is 4.87 g / m.

[0093] The drawing times in step S3 are 2 times, and the blended yarn finally obtained in step S4 has a gram weight of 0.4909 g / m and a yarn density of 2.295 g / cm 3 .

[0094] The blended yarns were unidirectionally laid and then compression molded at 260°C to evaluate the mechanical properties.

[0095] Performance Testing

[0096] The performance test results are shown in Table 1:

[0097] Table 1

[0098]

[0099]

[0100] The short fiber reinforced thermoplastic particles are glass fiber short fiber reinforced PA56 particles purchased from Ningbo Guorui New Materials with a brand name of GF30.

[0101] From the comparison results, it can be seen that the yarns prepared in the five embodiments have higher stiffness, strength and fiber content, and are superior to the traditional short fiber reinforced thermoplastic particles. The traditional method is to improve the stiffness and other properties by adding high modulus fibers. The present invention improves the orientation and uniformity of the glass fibers by performing specific opening, combing, drawing and spinning on the recycled fibers, and then adds thermoplastic resin fibers to tightly combine the glass fibers together, so that the stiffness, strength and other properties of the yarn are significantly improved. In Examples 1 and 5, the gain effect is significant.

[0102] Application Example 1

[0103] A recycled fiber reinforced composite material is prepared by a pultruded glass plate through a pultrusion process.

[0104] The pultrusion process includes a yarn frame and yarn guide, resin impregnation, preforming, mold heating and curing, demoulding post-processing and cutting.

[0105] During the mold heating and curing process, the mold length is 900 mm, the three temperature zones are 300 mm / section respectively, the pulling speed is 400 mm / min, and the mold temperatures in the three temperature zones are 140° C., 170° C., and 180° C.

[0106] Glass fiber density ρ = 2.61 g / cm 3

[0107] Example 1 Blended yarn linear density M = 2.4 g / m 3 (Take 2400Tex yarn as an example)

[0108] Recycled reinforcement fiber volume content 71.5%

[0109] Product area A = 105 × 5 = 525 mm 2

[0110] Recovered reinforcing fiber area A2 = 0.715A = 525 × 0.71.5 = 372.75 mm 2

[0111] Z = A2 × 2.61 / 2.4 = 408 shares

[0112] The dimensions of the pultruded glass sheet are width × thickness 105 × 5 mm.

[0113] Application Example 5

[0114] A recycled fiber reinforced composite material, a pultruded glass plate is prepared by a pultrusion process. The specific implementation method is the same as that of application example 1, except that the blended yarn of example 5 is used. The performance test results are shown in Table 2:

[0115] Table 2

[0116]

[0117]

[0118] The traditional glass sheet is SWANCOR RB507 recyclable pultruded glass sheet.

[0119] It can be seen from the results that using the blended yarns of Examples 1 and 5 to replace the pultruded bulked yarn has no effect on the final performance of the formed board and can be used with confidence.

Claims

1. A method for preparing high modulus recycled fiber blended yarn, characterized in that: The following steps are involved: S1 degrades and recycles waste composite materials to obtain recycled reinforcing fibers; S2 removes the residual resin on the surface of the recycled reinforcing fiber, and then mixes and loosens the fiber with the thermoplastic resin fiber. The opened fiber mixture passes through a carding machine to obtain a mixed yarn. S3 draws the mixed yarn through a drawing frame; After S4 drawing, the yarn is twisted through a spinning machine to form a yarn, and the outermost layer of the yarn is wrapped with filaments to obtain a blended yarn.

2. The method for preparing high modulus recycled fiber blended yarn according to claim 1, characterized in that: The length of the recycled reinforcement fibers is 40-200 mm.

3. The method for preparing high modulus recycled fiber blended yarn according to claim 1, characterized in that: The type of the recycled reinforcing fiber is selected from at least one of glass fiber, carbon fiber, basalt fiber and boron fiber.

4. The method for preparing high modulus recycled fiber blended yarn according to claim 1, characterized in that: The mass proportion of the recycled reinforcing fibers in the fiber mixture is 1-100%, excluding endpoints.

5. The method for preparing high modulus recycled fiber blended yarn according to claim 1, characterized in that: The mass ratio of the recycled reinforcing fiber to the thermoplastic resin fiber is (1-3):

1.

6. The method for preparing high modulus recycled fiber blended yarn according to claim 1, characterized in that: The thermoplastic resin fiber is selected from at least one of nylon, polyester fiber, polypropylene fiber, polyetheretherketone fiber, and polyphenylene sulfide fiber.

7. The method for preparing high modulus recycled fiber blended yarn according to claim 1, characterized in that: The number of opening times in step S2 is 1-5 times, and the gram weight of the mixed yarn is 3-7 g / m.

8. The method for preparing high modulus recycled fiber blended yarn according to claim 1, characterized in that: The drawing times in step S3 are 1-3 times, the weight of the blended yarn finally obtained in step S4 is 0.3-0.7 g / m, and the yarn density is 1-5 g / cm 3 .

9. Application of a method for preparing high modulus recycled fiber blended yarn, characterized in that: The prepared blended yarn was applied to the pultrusion process.

10. A recycled fiber reinforced composite material, characterized in that: The pultrusion process according to claim 9 is used to prepare the product.

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