Inorganic fiber chopped strand mat and preparation method thereof

Abstract

The invention relates to the technical field of chopped strand mat processing, and discloses an inorganic fiber chopped strand mat and a preparation method thereof.The inorganic fiber chopped strand mat comprises a framework fiber web and fixing fiber webs covering the upper surface and the lower surface of the framework fiber web, and the framework fiber web and the fixing fiber webs are fixed into a mat through spunlace; the framework fiber web is formed by carding framework fibers or freely dispersing the framework fibers to form a web, the fixed fiber web is formed by carding fixed fibers, the framework fibers are inorganic fibers, and the fixed fibers comprise synthetic fibers and inorganic fibers. The problems that existing inorganic fiber chopped strand mat production is high in production cost, fibers are prone to falling and layering, and the environment is prone to being polluted when the fibers are used are solved.

Description

Technical Field

[0001] The invention relates to the technical field of chopped strand mat processing, and in particular to an inorganic fiber chopped strand mat and a preparation method thereof. Background Art

[0002] Chopped strand mat refers to a fiber sheet or block material formed by processing fiber materials into short fiber segments through a specific processing technology. Inorganic fiber is a chemical fiber made from minerals. The main varieties include glass fiber, carbon fiber, basalt fiber, etc. Due to the excellent heat resistance, flame retardancy, sound insulation and other properties of inorganic fibers, inorganic fiber chopped strand mat is widely used in many fields, including construction, automobiles, aerospace, electronics, filtration and sound insulation.

[0003] At present, the production process of inorganic fiber chopped strand mat includes bonding and stitching. Bonding is to uniformly distribute the short fibers in an undirected manner, and then apply powder adhesive or emulsion adhesive to reinforce them. The finished product is called powder felt or emulsion felt; stitching is to uniformly lay the short fibers in an undirected manner and then reinforce them through needle-punching stitching. The finished product is called stitched felt. Inorganic fiber chopped strand mat is suitable for composite with resin as a reinforcing material for automobile, train and ship hulls. However, since both powder felt and emulsion felt contain adhesives, the chemical reaction between adhesive and resin not only affects the stability of the product, but also emits gas that affects the environment. At the same time, the sparse isolation of adhesives also affects the fusion of felt cloth and resin. In addition, due to the difference in the bonding strength of different adhesives, powder felt and emulsion felt are prone to fiber falling and delamination, and the product quality is uneven. Although stitched felt does not contain adhesive, it is reinforced by needle puncture, and its pinhole area accounts for more than 20% of the total area of ​​the felt cloth. The felt cloth can only be used after the pinholes are filled with resin. The resin filling of pinholes increases the production cost of inorganic fiber chopped strand mat. Summary of the invention

[0004] In view of this, the present invention provides an inorganic fiber chopped strand mat and a preparation method thereof, which solves the problems of high production cost, easy fiber falling and delamination, and easy environmental pollution in the existing inorganic fiber chopped strand mat production.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows.

[0006] In a first aspect, the present invention provides an inorganic fiber chopped strand mat, which comprises a skeleton fiber web and a fixed fiber web covering the upper and lower surfaces of the skeleton fiber web, wherein the skeleton fiber web and the fixed fiber web are fixed into a felt by hydroentanglement, wherein the skeleton fiber web is formed by combing skeleton fibers into a web or freely dispersing them into a web, wherein the fixed fiber web is formed by combing fixed fibers, wherein the skeleton fibers are inorganic fibers, and the fixed fibers include synthetic fibers and inorganic fibers.

[0007] Furthermore, the inorganic fibers include glass fibers, carbon fibers and basalt fibers, and the synthetic fibers include polyester fibers, polypropylene fibers, aramid fibers and polyphenylene sulfide fibers.

[0008] Since inorganic fibers such as glass fiber, carbon fiber, and basalt fiber are brittle and easy to break, they are not as spinnable as synthetic fibers such as polyester fiber, polypropylene fiber, aramid fiber, and polyphenylene sulfide fiber. Therefore, the inorganic fiber layers formed by glass fiber, carbon fiber, basalt fiber, etc. cannot be composited and fixed through the hydroentanglement process, and there are problems of easy fiber falling and stratification.

[0009] The fiber raw material of the skeleton fiber web of the present invention is inorganic fiber. After the opening and combing process, the inorganic fiber raw material can be relatively completely divided into single fiber state to form a uniform fiber web, or short-cut inorganic fiber filaments are uniformly dispersed on a fixed fiber web in a free-fall manner to form a skeleton fiber web.

[0010] The fiber raw materials for fixing the fiber web of the present invention include synthetic fibers and inorganic fibers. The synthetic fibers are spinnable, and although the inorganic fibers do not have spinning properties, after being combed into a single fiber state by a carding machine, a thin layer of mesh fibers is formed, which has a certain toughness and ensures the spunlace composite fixing effect.

[0011] Since the fixed fiber web has spinnability or toughness, the present invention covers the fixed fiber web on the upper and lower surfaces of the inorganic fiber skeleton fiber web, which on the one hand ensures the entanglement effect of water spunlace on the fibers of the fixed fiber web and the fibers of the skeleton fiber web, and on the other hand prevents the skeleton fibers in the skeleton fiber web from falling off, avoiding the accumulation of fallen fibers causing machine jams, breakage, etc., and ensuring the stable production of inorganic fiber chopped strands.

[0012] Preferably, the amount of the fixed fiber is 10-100 g / m 2 Single fiber web. The less the amount of fixed fibers used, the less the amount of fixed fibers contained in the formed fiber web. Too little fixed fibers in the fixed fiber web will affect the hydroentanglement of the fixed fibers and the skeleton fibers. When synthetic fibers are used as fixed fibers, too much fixed fibers in the fixed fiber web will affect the performance of the skeleton fibers.

[0013] In a second aspect, the present invention also provides a method for preparing the above-mentioned inorganic fiber chopped strand mat, which comprises the following steps: Step 1, preparing a skeleton fiber web and a fixed fiber web; the preparation method of the skeleton fiber web includes carding to form a web and freely dispersing to form a web, and the preparation method of the fixed fiber web includes carding to form a web and carding to form a web; Step 2: The upper and lower surfaces of the skeleton fiber web are covered with a fixed fiber web, and the skeleton fiber web and the fixed fiber web are fixed by a hydroentanglement method to obtain a preformed felt; Step 3: The preformed felt is subjected to the steps of liquid rolling, drying and shaping, rolling into coils, and slitting to obtain the inorganic fiber chopped strand mat.

[0014] Further, the carding into a web comprises the following steps: A. Opening: The opening machine loosens the fiber raw materials; B. Combing: The loosened fiber raw materials are combed into single fiber state by a carding machine to form a fiber web.

[0015] Further, the free dispersion into a network comprises the following steps: A. Short cutting: The filaments of the skeleton fiber are cut by a fiber short cutting machine to obtain short skeleton fiber filaments; preferably, the length of the short skeleton fiber filaments is 3-20 cm; B. Free dispersion into a web: The short fibers of the skeleton fiber are uniformly dispersed on the fixed fiber web in a free-falling manner to form a skeleton fiber web.

[0016] Furthermore, the carding and laying of the web comprises the following steps: A. Opening: The opening machine loosens the fixed fiber raw materials; B. Combing: The loosened fixed fiber raw materials are combed into single fiber state by a carding machine to form a fiber web; C. Laying the web: The web laying machine lays the carded web in a certain number of layers to form a web with a certain thickness; D. Stretching: The stretching machine stretches the laid fiber web to the required thickness.

[0017] Preferably, the web laying method includes cross-lapping and vertical folding lapping.

[0018] Compared with the prior art, the present invention has the following beneficial effects: 1. The inorganic fiber chopped strand mat provided by the present invention is reinforced by physical means, does not contain adhesive, and has no gas emissions generated by the reaction between adhesive and resin, and is highly environmentally friendly; 2. The inorganic fiber chopped strand mat provided by the present invention does not contain an adhesive. Without an adhesive, there will be no sparse isolation film caused by the adhesive, so the mat can be quickly infiltrated in the resin, thereby increasing the use rate; 3. The inorganic fiber chopped strand mat provided by the present invention is reinforced by spunlace, has small pores, no pinholes, does not require resin filling, and has low production cost; the spunlace process is an existing mature technology, the process flow is simple, and it is easy to operate; 4. The inorganic fiber chopped strand mat prepared by the spunlace composite skeleton fiber net and the fixed fiber net has no fiber shedding and delamination phenomenon, has excellent strength and toughness, and has high product quality; 5. The inorganic fiber chopped strand mat provided by the present invention has a structure in which a fixed fiber web is covered on the upper and lower surfaces of a skeleton fiber web formed by inorganic fibers. When polyester fiber is used as the fiber raw material of the fixed fiber web, the inorganic fiber chopped strand mat can be endowed with more properties, such as anti-ultraviolet rays, anti-aging, and anti-acid and alkali corrosion. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 The process flow chart of preparing glass fiber chopped strand mat in Example 1 is as follows; Figure 2 The process flow chart of preparing glass fiber chopped strand mat in Example 2 is as follows; Figure 3 The process flow chart of preparing glass fiber chopped strand mat in Example 3 is as follows; Figure 4 The process flow chart of preparing glass fiber chopped strand mat in Example 4 is as follows; Figure 5 This is a real picture of glass fiber chopped powder mat; Figure 6 This is a real picture of glass fiber chopped strand mat; Figure 7 This is a real picture of the glass fiber chopped strand mat prepared in Example 1. DETAILED DESCRIPTION

[0020] The present invention is further described below in conjunction with the accompanying drawings and specific embodiments. It is understood that the specific embodiments and the accompanying drawings are only exemplary descriptions of the present invention and should not be regarded as the entirety of the present invention or as a limitation or restriction to the technical solution of the present invention. Unless otherwise specified, the raw materials used in the specific embodiments can be obtained through conventional commercial channels.

[0021] Embodiment 1: Select glass fiber as the skeleton fiber and polyester fiber as the fixed fiber. Figure 1 The process flow is used to prepare glass fiber chopped strand mat, wherein the amount of skeleton fiber is 200 g of glass fiber per square meter of fiber web, and the amount of fixed fiber is 10 g of polyester fiber per square meter of fiber web.

[0022] The specific preparation steps are as follows: Step 1: After the glass fiber raw material is loosened by the opener, it is quantitatively fed into the carding machine, and the carding machine is combed into a single fiber state to form a skeleton fiber web; Step 2: After the polyester fiber raw materials are loosened by the opener, they are quantitatively fed into the 1# carding machine and the 2# carding machine respectively. A part of the polyester fiber raw materials is carded into a single fiber state by the 1# carding machine to form a single fiber web. The web laying machine then stacks the single fiber web into a fiber web with a certain thickness according to a certain number of layers, and then the single fiber web is thinned by the drafting machine to form a lower fixed fiber web; and a part of the polyester fiber raw materials is carded into a single fiber state by the 2# carding machine to form an upper fixed fiber web; Step 3: After the lower fixed fiber web is combined with the skeleton fiber web, the upper fixed fiber web is combined on the surface of the skeleton fiber web, and then the glass fiber chopped strand mat is prepared through water spunlacing, liquid squeezing, drying and shaping, rolling into rolls, and slitting. The obtained product is shown in Figure 7 As shown, it can be seen that the surface of the glass fiber chopped strand mat is flat and smooth.

[0023] Embodiment 2: Select glass fiber as the skeleton fiber and polyester fiber as the fixed fiber. Figure 2 The process flow shown is used to prepare glass fiber chopped strand mat, wherein the amount of skeleton fiber is 200 g of glass fiber per square meter of fiber web, and the amount of fixed fiber is 100 g of polyester fiber per square meter of fiber web.

[0024] The specific preparation steps are as follows: Step 1: After the glass fiber raw material is loosened by the opener, it is quantitatively fed into the carding machine, and the carding machine is combed into a single fiber state to form a skeleton fiber web; Step 2: After the polyester fiber raw material is loosened by the opener, it is quantitatively fed into the 1# carding machine and the 2# carding machine respectively, and is carded into a single fiber state by the 1# carding machine to form a lower fixed fiber web, and is carded into a single fiber state by the 2# carding machine to form an upper fixed fiber web; Step 3: After the lower fixed fiber web is combined with the skeleton fiber web, the upper fixed fiber web is combined on the surface of the skeleton fiber web, and then the glass fiber chopped strand mat is prepared through water entanglement, liquid squeezing, drying and shaping, rolling into rolls, and slitting steps.

[0025] Embodiment 3: Select glass fiber as the skeleton fiber and polyester fiber as the fixed fiber. Figure 3 The process flow shown is used to prepare glass fiber chopped strand mat, wherein the amount of skeleton fiber is 200 g of glass fiber per square meter of fiber web, and the amount of fixed fiber is 10 g of polyester fiber per square meter of fiber web.

[0026] The specific preparation steps are as follows: Step 1: The glass fiber filaments are chopped by a chopped machine to obtain glass fiber short filaments, which are fed into a feeder; Step 2: After the polyester fiber raw materials are loosened by the opener, they are quantitatively fed into the 1# carding machine and the 2# carding machine respectively. A part of the polyester fiber raw materials is carded into a single fiber state by the 1# carding machine to form a single fiber web. The web laying machine then stacks the single fiber web into a fiber web with a certain thickness according to a certain number of layers, and then the single fiber web is thinned by the drafting machine to form a lower fixed fiber web; and a part of the polyester fiber raw materials is carded into a single fiber state by the 2# carding machine to form an upper fixed fiber web; Step 3: The feeder makes the glass fiber short filaments evenly dispersed on the lower fixed fiber net in a free fall manner to form a skeleton fiber net, and then the surface of the skeleton fiber net is merged with the upper fixed fiber net, and the glass fiber chopped strand mat is prepared through the steps of water entanglement, liquid squeezing, drying and shaping, rolling into rolls, and slitting.

[0027] Embodiment 4: Select glass fiber as the skeleton fiber and polyester fiber as the fixed fiber. Figure 4 The process flow shown is used to prepare glass fiber chopped strand mat, wherein the amount of skeleton fiber is 200 g of glass fiber per square meter of fiber web, and the amount of fixed fiber is 50 g of polyester fiber per square meter of fiber web.

[0028] The specific preparation steps are as follows: Step 1: The glass fiber filaments are chopped by a chopped machine to obtain glass fiber short filaments, which are fed into a feeder; Step 2: After the polyester fiber raw material is loosened by the opener, it is quantitatively fed into the 1# carding machine and the 2# carding machine respectively, and is carded into a single fiber state by the 1# carding machine to form a lower fixed fiber web, and is carded into a single fiber state by the 2# carding machine to form an upper fixed fiber web; Step 3: The feeder makes the glass fiber short filaments evenly dispersed on the lower fixed fiber net in a free fall manner to form a skeleton fiber net, and then the surface of the skeleton fiber net is merged with the upper fixed fiber net, and the glass fiber chopped strand mat is prepared through the steps of water entanglement, liquid squeezing, drying and shaping, rolling into rolls, and slitting.

[0029] Embodiment 5: Glass fibers were selected as skeleton fibers and fixed fibers, and glass fiber chopped strand mats were prepared according to the steps of Example 1. The amount of skeleton fibers was 200 g of glass fibers per square meter of fiber web, and the amount of fixed fibers was 15 g of glass fibers per square meter of fiber web.

[0030] Embodiment 6: Carbon fiber was selected as the skeleton fiber and polyester fiber was selected as the fixed fiber, and carbon fiber chopped strand mat was prepared according to the steps of Example 1. The amount of skeleton fiber was 200 g of carbon fiber per square meter of fiber web, and the amount of fixed fiber was 10 g of polyester fiber per square meter of fiber web.

[0031] Embodiment 7: Basalt fiber was selected as the skeleton fiber and polyester fiber was selected as the fixed fiber, and basalt fiber chopped mat was prepared according to the steps of Example 1. The amount of the skeleton fiber was 200 g of basalt fiber per square meter of fiber web, and the amount of the fixed fiber was 10 g of polyester fiber per square meter of fiber web.

[0032] Embodiment 8: The same as Example 1, except that polypropylene fibers are selected as fixed fibers.

[0033] Embodiment 9: The same as Example 1, except that aramid fiber is selected as the fixed fiber.

[0034] Embodiment 10: The same as Example 1, except that polyphenylene sulfide fiber is selected as the fixed fiber.

[0035] Comparative Example 1: According to the existing process, 200g of glass fiber chopped powder mat was prepared. Figure 5 As shown, it can be seen that the fibers in the powder felt are crisscrossed and extend out of the felt, and the surface is very rough.

[0036] Comparative Example 2: According to the existing process, 200g of glass fiber chopped stitched mat (sewing thread is made of glass fiber) is prepared. Figure 6 As shown, it can be seen that the fiber filaments of the stitched felt also extend out of the felt, the surface is rough, and the pinholes of the stitched felt are large. After testing, the pinhole area accounts for 22% of the total area of ​​the felt cloth, and the pinholes need to be filled with resin. Since the price of resin is three times that of glass fiber chopped strand mat (glass fiber mat), the present invention adopts spunlace compounding, which does not contain pinholes, can reduce the amount of resin filling, and save production costs by more than 2,000 yuan / ton.

[0037] The inorganic fiber chopped strand mats (glue-free mats) prepared in the above-mentioned Examples 1 to 10 and the powder mat prepared in Comparative Example 1 were tested for fiber shedding using a Martindale tester (model ASR-1014Z). The testing method is as follows: the Martindale tester brings the test sample into contact with a standard abrasive under a specified pressure, and moves the test sample relative to the abrasive in a Lissajous figure motion trajectory. Each rotation is recorded as one operation, and the fiber shedding is observed and recorded after each operation. The results are shown in Table 1 below.

[0038]

[0039] It can be seen from Table 1 that the adhesive-free felts provided in Examples 1 to 10 had no fiber falling off after being in contact with the abrasive and rotating continuously for 20 circles, which proves that the inorganic fiber chopped strand felt provided by the present invention has no fiber shedding and delamination.

[0040] The strength and toughness of the inorganic fiber chopped strand mats (glue-free mats) prepared in Examples 1 to 10 and the powder mat prepared in Comparative Example 1 were tested using a strength tester (model YG026B). The size of the tested samples was 315 mm long × 150 mm wide. The results are shown in Table 2 below.

[0041]

[0042] It can be seen from Table 2 that the adhesive-free felt provided by Examples 1 to 10 of the present invention has significantly improved strength and toughness compared with the powder felt provided by Comparative Example 1, and the data of Examples 1 to 10 show that as the type of fixed fibers in the adhesive-free felt changes, its strength and toughness also change. It can be seen from Examples 1 to 4 that the strength and toughness of the adhesive-free felt increase with the increase in the amount of fibers in the fixed fiber web, indicating that the fixed fiber web has a greater contribution to the strength of the adhesive-free felt. The setting of the fixed fiber web of the present invention gives the inorganic fiber chopped felt better product performance, so that it has excellent strength and toughness.

[0043] In summary, the inorganic fiber chopped strand mat provided by the present invention has a smooth surface, has excellent strength and toughness compared to powdered felt, and does not suffer from fiber shedding or stratification; compared to stitched felt, it does not contain pinholes and does not require resin filling, thus saving production costs.

[0044] The above descriptions are merely embodiments of the present invention and are not intended to limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made using the contents of the present invention specification and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. An inorganic fiber chopped strand mat, characterized in that: It includes a skeleton fiber web and a fixed fiber web covering the upper and lower surfaces of the skeleton fiber web, the skeleton fiber web and the fixed fiber web are fixed into a felt by water entanglement, the skeleton fiber web is formed by combing skeleton fibers into a web or freely dispersing them into a web, the fixed fiber web is formed by combing fixed fibers, the skeleton fibers are inorganic fibers, and the fixed fibers include synthetic fibers and inorganic fibers.

2. The inorganic fiber chopped strand mat according to claim 1, characterized in that: The inorganic fibers include glass fibers, carbon fibers and basalt fibers, and the synthetic fibers include polyester fibers, polypropylene fibers, aramid fibers and polyphenylene sulfide fibers.

3. The inorganic fiber chopped strand mat according to claim 1, characterized in that: The amount of the fixed fiber is 10-100g / m 2 Single fiber mesh.

4. The method for preparing the inorganic fiber chopped strand mat according to any one of claims 1 to 3, characterized in that: The following steps are involved: Step 1, preparing a skeleton fiber web and a fixed fiber web; the preparation method of the skeleton fiber web includes carding to form a web and freely dispersing to form a web, and the preparation method of the fixed fiber web includes carding to form a web and carding to form a web; Step 2: The upper and lower surfaces of the skeleton fiber web are covered with a fixed fiber web, and the skeleton fiber web and the fixed fiber web are fixed by a hydroentanglement method to obtain a preformed felt; Step 3: The preformed felt is subjected to the steps of liquid rolling, drying and shaping, rolling into coils, and slitting to obtain the inorganic fiber chopped strand mat.

5. The preparation method according to claim 4, characterized in that: The carding process comprises the following steps: A. Opening: The opening machine loosens the fiber raw materials; B. Combing: The loosened fiber raw materials are combed into single fiber state by a carding machine to form a fiber web.

6. The preparation method according to claim 4, characterized in that: The free dispersion into a network comprises the following steps: A. Short cutting: The filaments of skeleton fiber are cut by a fiber short cutting machine to obtain short skeleton fiber filaments; B. Free dispersion into a web: The short fibers of the skeleton fiber are evenly dispersed in an undirected manner on the fixed fiber web to form a skeleton fiber web.

7. The preparation method according to claim 6, characterized in that: The length of the skeleton fiber staple is 3-20 cm.

8. The preparation method according to claim 4, characterized in that: The carding and laying of the web comprises the following steps: A. Opening: The opening machine loosens the fixed fiber raw materials; B. Combing: The loosened fixed fiber raw materials are combed into single fiber state by a carding machine to form a fiber web; C. Laying the web: The web laying machine lays the carded web in a certain number of layers to form a web with a certain thickness; D. Stretching: The stretching machine stretches the laid fiber web to the required thickness.

9. The preparation method according to claim 8, characterized in that: The web laying methods include cross-lapping and vertical folding.

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