Ultraviolet-proof knitted fabric

Abstract

The invention discloses an ultraviolet-proof knitted fabric. The knitted fabric is formed by weaving two-sided tissues and has a surface A and a surface B, the height of the cross section is h, the depth of a concave part of the surface A on the cross section is h1, the depth of a concave part of the surface B on the cross section is h2, h, h1 and h2 meet the following formulas: (h1 + h2) / h is more than 0.40 and less than or equal to 1.50, h1 / h is more than 0.20 and less than or equal to 0.75, and the UPF value of the knitted fabric is more than 30. The knitted fabric is endowed with more excellent air permeability and ultraviolet resistance through reasonable weave structure design, when the ultraviolet resistance UPF value is 30 or above, the ventilation capacity exceeds 200 cm < 3 > / (cm < 2 >. S), and the knitted fabric is suitable for making sports and leisure clothes, POLO shirts, T-shirts and the like.

Description

UV-resistant knitted fabric Technical Field

[0001] The invention relates to an anti-ultraviolet knitted fabric, in particular to a knitted fabric with superior air permeability and anti-ultraviolet properties. Background Art

[0002] With global warming and increased ultraviolet radiation, demand for UV protection in everyday clothing is increasing. Existing fabrics mostly achieve UV protection through a dense structure. While these products offer good UV protection, they often suffer from low airflow, a stiff feel, and poor wearing comfort.

[0003] There has been much research on how to improve the breathability of UV-resistant fabrics. For example, Chinese patent document CN108532108B discloses a cool UV-resistant knitted fabric, which specifically discloses that the knitted fabric is composed of direct mesh and indirect mesh, with the distribution rate of direct mesh on the surface and inside of the fabric being less than 3%, and the distribution rate of indirect mesh on the surface and inside of the fabric being 5-30%. The fabric is adjusted in both horizontal and vertical density through post-finishing, achieving excellent breathability while ensuring UV resistance. However, it requires post-dyeing stretching and shaping to obtain a suitable mesh distribution rate, and the controllability of the process is relatively poor.

[0004] For example, Chinese patent document CN108621482A discloses a UV-proof breathable knitted fabric, which specifically discloses that the fabric includes a surface layer and an inner layer, both of which have meshes, and the distance between the center of the projection A' of the surface mesh A on the inner layer and the center of the inner mesh B is 0.20 to 5.00 mm. It has relatively excellent air permeability and UV protection, but the ventilation volume is greater than 200 cm 3 / cm 2 The UPF value at s is less than 30.

[0005] For example, Japanese Patent Document No. 6128984 discloses polyester false-twist low-melting yarn and multi-layer structure fabrics. Specifically, it is disclosed that the polyester false-twist low-melting yarn has untwisted portions, over-twisted portions, and crimped portions distributed alternately in the length direction, the average length of the untwisted portions is less than 7 mm, the average length of the over-twisted portions is more than 7 mm, the degree of melting in the length direction of the melting yarn is less than 50%, and the porosity of the cross-section of the untwisted portions is 10% to 47%. The fabric made therefrom has both high water absorption and quick-drying properties and breathability, and has a unique surface feel, but requires the use of melting yarns of a specific structure, which is costly and complex in process.

[0006] For example, Japanese Patent No. 7357464 discloses a breathable UV-A shielding knitted fabric, specifically a double-knitted fabric comprising 70% by weight or more of false twisted yarn, one side of which is a plain stitch, with a cover factor of 850 to 1200 and an apparent density of 0.18 to 0.24 g / cm 3 , the average transmittance of UV-A is less than 12%, and the ventilation volume is 150-300cc / cm 2 / sec, wherein the false twisted yarn is composed of a synthetic fiber containing 2 to 12 wt% of inorganic oxide particles and / or a core-sheath composite fiber containing 3 to 20 wt% of inorganic oxide particles in the core and 3 wt% or less of inorganic oxide particles in the sheath, and has high air permeability, UV protection and a cool feeling, but the ventilation volume exceeds 200 cm 3 / (cm 2 ·s) needs to be further improved.

[0007] Summary of the Invention

[0008] The purpose of the present invention is to provide a knitted fabric which has low cost, simple and easy manufacturing method, and has both superior air permeability and UV protection.

[0009] The technical solutions of the present invention are as follows:

[0010] The knitted fabric of the present invention is woven from a double-sided structure, has an A side and a B side, a cross-sectional height of h, a depth of a concave portion of the A side of h1, and a depth of a concave portion of the B side of h2, h, h1, and h2 satisfy the following relationship: 0.40<(h1+h2) / h≤1.50, 0.20

[0011] The present invention endows the knitted fabric with more superior air permeability and UV resistance through reasonable organizational structure design. When the UV resistance UPF value is above 30, the ventilation volume exceeds 200cm 3 / (cm 2 ·s), suitable for making sportswear, POLO shirts, T-shirts, etc. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] FIG1 is a digital microscope photograph of a cross section of a knitted fabric of the present invention.

[0013] FIG2 is a schematic diagram of tissue 1 in Example 1.

[0014] FIG3 is a schematic diagram of tissue 7 in Example 9.

[0015] FIG4 is a schematic diagram of tissue 8 in Example 10.

[0016] ​FIG5 is a schematic diagram of tissue 9 in Example 11.

[0017] FIG6 is a schematic diagram of the tissue 11 in Example 16.

[0018] FIG7 is a schematic diagram of the tissue 12 in Example 18. DETAILED DESCRIPTION

[0019] When sunlight shines on one side of a fabric, the light transmittance is significantly affected by the fabric's thickness and the depth of the concave portions of that side. The knitted fabric of the present invention is woven from a double-sided weave and has an A side and a B side. In the present invention, the A side and the B side are not specifically defined; if one side is arbitrarily designated as the A side (or the B side), the other side is designated as the B side (or the A side). The knitted fabric of the present invention has excellent UV protection, with a UPF value (ultraviolet protection factor) of more than 30. The cross-sectional height is h, the depth of the concave portion of the A side is h1, and the depth of the concave portion of the B side is h2. When (h1+h2) / h is less than or equal to 0.40, although the fabric has good UV protection, the fabric is thick and has poor air permeability, which easily produces a stuffy feeling. When (h1+h2) / h is greater than 1.50, a large number of straight mesh holes appear between the adjacent concave portions of the A side and the B side. Although the air permeability of the fabric is significantly increased, the UV protection is greatly reduced. Therefore, the present invention requires that h, h1 and h2 satisfy the following relationship: 0.40<(h1+h2) / h≤1.50, and preferably 0.40<(h1+h2) / h≤1.20. Furthermore, the present invention requires that 0.20 < h1 / h ≤ 0.75, so that both air permeability and UV protection can be taken into consideration, and preferably 0.30 < h1 / h ≤ 0.75.

[0020] Considering that if the projection A' of the concave part of surface A on surface B is in the same vertical row as the concave part of surface B, straight-through mesh holes may be formed, thereby increasing the ultraviolet transmittance, therefore, in the present invention, it is preferred that the projection A' of the concave part of surface A on surface B is not in the same vertical row as the concave part of surface B.

[0021] Preferably, the longitudinal section of the knitted fabric of the present invention includes three situations: (1) having two longitudinal section shapes, in which in longitudinal section 1, side A has no concave portion and side B has continuous concave portion, and in longitudinal section 2, side A has discontinuous concave portion and side B has no concave portion; (2) having two longitudinal section shapes, in which in longitudinal section 1, side A has no concave portion and side B has discontinuous concave portion, and in longitudinal section 2, side A has discontinuous concave portion and side B has no concave portion; (3) having only one longitudinal section shape, in which both side A and side B have discontinuous concave portion. Such a concave configuration can ensure the fabric's UV protection while taking into account high breathability. The formation of different longitudinal section shapes is mainly achieved by configuring appropriate tissues on different paths. For example, the first knitting pattern on surface A is a tuck stitch, the second and third knitting patterns are loop stitches, and these three knitting patterns are repeatedly woven in one cycle; if all knitting patterns on surface B are loop stitches, two longitudinal cross-sectional shapes can be formed. In longitudinal cross-sectional shape 1, surface A has no concave portion and surface B has continuous concave portion; in longitudinal cross-sectional shape 2, surface A has discontinuous concave portion and surface B has no concave portion.

[0022] When the knitted fabric of the present invention has two longitudinal cross-sectional configurations, it is preferred that the width W1 of the recesses on the A side and the width W2 of the recesses on the B side be less than or equal to three wales. If the recess width is greater than three wales, the individual recesses become larger, prone to deformation and skewness, and tend to increase the number of mesh holes. Furthermore, the fabric surface becomes loose, and problems such as thread snagging may occur. Therefore, this is not preferred.

[0023] When the knitted fabric of the present invention has two longitudinal cross-sectional configurations, with side A having no concave portions and side B having continuous concave portions in longitudinal cross-sectional configuration 1, and side A having discontinuous concave portions and side B having no concave portions in longitudinal cross-sectional configuration 2, to improve breathability, it is considered to set a relatively large concave coverage ratio on side B and a relatively small concave coverage ratio on side A. The concave coverage ratio here refers to the proportion of the concave portions on the surface on which they are located. If the concave coverage ratio on side A is less than 5%, the fabric's UV protection is enhanced, but its breathability tends to decrease. If the concave coverage ratio on side A is greater than 30%, the fabric's breathability increases significantly, the concave portions on sides A and B may overlap, and the proportion of straight mesh holes on the fabric increases, which tends to weaken the UV protection effect and may even affect wearing comfort. To achieve both superior UV protection and breathability, it is preferred that, in a complete fabric, the concave coverage ratio a on side A be 5% to 30%, and the concave coverage ratio b on side B be 40% to 60%. The coverage ratio a of the concave portions of the A surface is more preferably 10% to 20%, and the coverage ratio b of the concave portions of the B surface is more preferably 45% to 55%.

[0024] Preferably, within a complete weave, at least one course with looped stitches has a fineness difference with the other courses, and this fineness difference is between 30 and 100 dtex. Specifically, within all courses of a complete weave (i.e., all courses on both side A and side B), at least one course with looped stitches has a fineness difference with the other courses. If the fineness difference is less than 30 dtex, the number of pores in the fabric decreases, leading to a decrease in breathability. If the fineness difference is greater than 100 dtex, the number of through-holes increases, leading to a decrease in UV protection, and therefore is not preferred. A fineness difference of 30 to 50 dtex is more preferred.

[0025] When the knitted fabric of the present invention has only one longitudinal cross-sectional shape, if the sum of the concave coverage a on side A and the concave coverage b on side B in a complete weave (i.e., a+b>110%), the fabric may have a large number of through-holes, which may weaken its UV protection and even affect wearer comfort. If a+b<60%, the fabric's breathability may decrease. If |ab|>50%, the concave coverage on one side may be excessive and on the other side may be insufficient, which may affect snagging and weaving properties. Therefore, in the present invention, it is preferred that the coverage a and coverage b satisfy the following relationship: 60% ≤ a+b ≤ 110%, and 0 ≤ |ab| ≤ 50%, and more preferably 80% ≤ a+b ≤ 110%, and 0 ≤ |ab| ≤ 20%.

[0026] The yarn used in the knitted fabric of the present invention is not particularly limited, but preferably uses UV-resistant yarn, with a content of no less than 50% by weight. If the content of UV-resistant yarn is less than 50% by weight, the fabric's reflectivity against ultraviolet rays tends to decline. The fiber type, cross-section, and manufacturing method of the UV-resistant yarn are not particularly limited in the present invention. The yarn may be made of polyester (PET), polyacrylonitrile, polyamide, polyvinyl formal, or polypropylene, with PET being preferred for cost considerations. The cross-section may be a standard circular shape or may have a triangular, cross-shaped, core-sheath, or laminated shape.

[0027] The UV-proof yarn can be obtained by adding inorganic particles during spinning, or by attaching inorganic particles to the fiber through coating or other methods. Preferably, it is obtained by adding inorganic particles during spinning. The UV-proof yarn in the present invention is preferably a yarn with an inorganic particle content of 2.2% by weight or more, and more preferably a yarn with an inorganic particle content of 7.0% by weight or more. The higher the content of inorganic particles in the UV-proof yarn, the stronger the light reflection effect, the lower the light transmittance, and the better the UV-proof performance of the fabric. The inorganic particles here are not particularly limited and can be titanium dioxide (TiO2), zinc oxide (ZnO), talc, clay, calcium carbonate, etc. The UV-proof yarn can be filament or multifilament yarn. On the basis of ensuring high air permeability and high UV protection, considering factors such as gram weight, the fineness of the spun yarn used in the present invention is preferably 30 to 80 dtex; the fineness of the filament or multifilament yarn used is preferably 22 to 165 dtex. When the yarn is formed from fibers having different inorganic particle contents, it is considered to be UV-blocking yarn if the average inorganic particle content is greater than 2.2% by weight.

[0028] When the knitted fabric of the present invention is formed from the aforementioned UV-blocking yarn and other yarns, the other yarns are not particularly limited and can be selected as needed. Examples include semi-matt PET DTY (TiO2 content of 0.25 wt%) and conventional polyamide DTY (TiO2 content of 0). Preferably, at least one of the A and B sides of the present invention is formed entirely from the aforementioned UV-blocking yarn. In this case, the fabric exhibits even superior UV resistance.

[0029] The knitted fabric of the present invention is mainly used as spring, summer and autumn clothing, and its gram weight is preferably 100-250g / m 2 , more preferably 120 to 160 g / m 2 .

[0030] As a preference, the ventilation capacity of the knitted fabric of the present invention is greater than 200cm 3 / (cm 2 ·s), further preferably at 210cm 3 / (cm 2 s) or above.

[0031] The knitted fabric of the present invention can be used to make sportswear, T-shirts or POLO shirts and the like.

[0032] The fabric of the present invention is woven using a double-sided knitting machine. The type of double-sided knitting machine is not particularly limited and can be a conventional double-sided circular knitting machine, a jacquard double-sided circular knitting machine, a double-sided warp knitting machine, or a double-sided forming machine. A conventional double-sided circular knitting machine or a double-sided warp knitting machine is preferred. For weft knitted fabrics, a combination of two or more of loop formation, tuck stitch, and float stitch is preferred. For warp knitted fabrics, one or more of a variable warp plain, chain weft inlay, and jacquard weft inlay are preferred. For the cost and convenience of mass production, a combination of tuck stitch and loop formation, or a variable warp plain, is preferred.

[0033] During the fabric manufacturing process of the present invention, conventional processing conditions are used for scouring, dyeing, shaping, and finishing. Fluorescent white dye is preferably used for white dyeing. The scouring agent, dyeing acid, hydrophilic agent, softener, etc. used in each step of the present invention can be commercially available or prepared in-house, with the preferred dosage being 0.1 to 20 g / L.

[0034] The present invention is further described below with reference to the following examples and comparative examples. The test methods for the various parameters involved in the present invention are as follows:

[0035] (1) Cross-section height and concave depth

[0036] According to the "Sampling and Sample Preparation" specified in the JIS L 0105:2020 standard, 10 samples of approximately 5 cm horizontally and 1 cm vertically were cut along the horizontal direction of the fabric with a blade. One of the samples was taken and its cross-section was photographed using a KEYENCE VHX-2000 digital microscope (Figure 1), as follows: First, one side of the sample was arbitrarily determined to be side B (the other side was side A), and the sample was placed face down on an observation table with double-sided tape attached under a tension-free state. A 50g weight (Jun Teng 304 stainless steel F1 grade) was gently placed on the sample. After 10 seconds, it was moved to the next position and this action was repeated so that the contact part of the sample and the observation table was fully adhered to the double-sided tape of the observation table. The prepared sample was placed under standard atmospheric conditions for 1 hour before testing. The observation table was turned over so that the cross-section of the sample was facing up, and it was placed under a microscope for photography. The microscope magnification was adjusted to 100 times, and the ruler function was used to measure the sample. Take the zero-line on the fitting surface between the specimen and the double-sided tape, take 20 points at equal distances in the horizontal direction (the distance between the left and right endpoints in the photo divided by 20), record the vertical distance between each point and the observation table, and take the average value. Use the average value as the basis to draw the zero-line. Take 20 highest points at equal distances in the horizontal direction along one side of surface A (the method is the same as above) (the highest point refers to the highest point reached by the fiber in the vertical direction of the photo). If the edge point is located in the concave part (the concave part refers to the area in the cross section that is lower than 1 / 2 of the yarn cross-section height of the weave points on both sides), it is discarded. The number of discarded edge points is recorded as n, that is, the number of edge points located in the non-concave part is retained, and its number is 20-n. Record the vertical distance between the edge points in the non-concave part and the zero-line, remove the maximum and minimum values, and take the average value of the remaining as the cross-sectional height of the specimen. Use the average value as the basis to draw a straight line a parallel to the zero-line. Next, a perpendicular line was drawn into the concave portion on the B side using the 0-position line as the horizontal reference line. The maximum value among these perpendicular lines was the depth of the concave portion. After measuring all the concave portions on the B side, the average value was taken as the depth of the concave portion on the B side of the sample. Next, a perpendicular line was drawn into the concave portion on the A side using the straight line a as the horizontal reference line. The maximum value among these perpendicular lines was the depth of the concave portion. After measuring all the concave portions on the A side, the average value was taken as the depth of the concave portion on the A side of the sample. The remaining nine samples were measured using the same method, and the average values ​​were taken as the cross-sectional height h, the concave depth of the A side h1, and the concave depth of the B side h2 of the present invention.

[0037] (2) Coverage of concave portion

[0038] According to the "Sampling and Sample Preparation" section of JIS L 0105:2020, 10 5 cm x 5 cm specimens were cut (cut along the rows and widths of the fabric). One of these specimens was placed horizontally and tension-free on the observation platform of a KEYENCE VHX2000 digital microscope. The microscope magnification was adjusted to 50x. The number of wales and rows with looped weave in a complete weave on the surface was counted. The product of these two numbers was calculated as the number of weave points and recorded as P (unit: number). For example, if a complete weave has 2 wales and 4 rows with looped weave, the number of weave points in this weave cycle is 8 (i.e., 2 x 4). Similarly, the number of wales and rows containing concave areas was counted. The number of concave weave points on the surface was then calculated as p1 (unit: number). The concave weave coverage (%) was calculated as follows: p1 / (P+p1)*100%. The remaining 9 samples were measured in the same manner, and the average values ​​were taken as the coverage of the concave portions of the present invention.

[0039] (3) Ventilation volume

[0040] Based on JIS L 1096:2010A method.

[0041] (4) UV protection (UPF value)

[0042] According to JIS L 1925:2019 standard.

[0043] (5) Content of inorganic particles in UV-resistant yarn

[0044] ① First, boil the crucible with hydrochloric acid (1:4) for 1 to 2 hours, wash and dry it; place it in a high-temperature furnace at 500-550℃ and burn it for 1 hour, move it to the furnace mouth and cool it to about 200℃, then move it into a dryer, cool it to room temperature and weigh it; then place the cooled crucible into the high-temperature furnace and burn it for 30 minutes, take it out, cool it and weigh it until it reaches a constant weight, which is recorded as m1 (the difference between the two weighings should not exceed 0.5mg. If it exceeds 0.5mg, continue to place it in the high-temperature furnace and burn it). The scale value of the analytical balance is 0.0001g / scale;

[0045] ② Take 5g of yarn containing inorganic particles from the fabric as a sample, then put 5g of the sample into a crucible and weigh it and record it as m2;

[0046] ③ First, heat the crucible in an electric furnace on low heat to fully carbonize the sample until it is smokeless. Then place it in a high-temperature furnace for 4 hours. After removing the crucible and cooling it to below 200°C, place it in a desiccator for 40 minutes to cool it to room temperature. Weigh and record the weight. Place it in the high-temperature furnace again and continue burning for 30 minutes. Remove it, cool it, and weigh it as m3 (the difference between the two weighings should not exceed 0.5 mg. If it exceeds 0.5 mg, continue to place it in the high-temperature furnace to burn). Then calculate the ash percentage as the content of inorganic particles in the yarn according to the following formula:

[0047] Ash content (%) = [(m3-m1) / (m2-m1)] × 100%

[0048] Where: m1 is the mass of the empty crucible (g)

[0049] m2 is the mass of the sample plus the empty crucible (g)

[0050] m3 is the mass of residual ash plus empty crucible (g)

[0051] ④ Repeat the above steps ① to ③ to measure 3 groups of samples in total, obtain 3 groups of data, and take the average value as the content of the inorganic particles of the present invention.

[0052] (6) Content of UV-resistant yarn in fabric

[0053] First, all yarns in a complete weave of the fabric are disassembled, and the content of inorganic particles in each yarn is measured according to the test method (5) for the content of inorganic particles in UV-resistant yarns, thereby determining the number of yarns where UV-resistant yarns (with an inorganic particle content of more than 2.2% by weight) are located in a complete weave; then, a 10cm*10cm sample of fabric is taken, all yarns are disassembled, and UV-resistant yarns and other yarns are distinguished according to the number of yarns where UV-resistant yarns are located. The weight x (unit: g) of the UV-resistant yarn and the weight y (unit: g) of all yarns are weighed respectively, and calculated according to the following formula:

[0054] Content of UV-proof yarn (weight %)=(x / y)*100%.

[0055] Example 1

[0056] On a 28G double-sided circular knitting machine, weaving was performed using the weave 1 shown in FIG2 , with six passes forming a complete weave. Yarn 1 (TiO2 content: 2.5 wt%) was made of 54 dtex / 72f round-cross-section, fully matte PET DTY in the third pass, and yarn 2 (TiO2 content: 2.5 wt%) was made of 84 dtex / 36f round-cross-section, fully matte PET DTY in the remaining passes. The knitted fabric of the present invention was then produced through pretreatment (scouring agent: 1 g / L), dyeing (disperse dye: 130°C for 30 minutes), finishing (water-absorbing agent PR-99Z, manufactured by Nichika Chemical Co., Ltd.), and setting (170°C for 90 seconds). Parameters are detailed in Tables 1 and 2. The resulting knitted fabric had two longitudinal cross-sectional morphologies: longitudinal cross-sectional 1, in which side A had no concave portions and side B had continuous concave portions; longitudinal cross-sectional 2, in which side A had discontinuous concave portions and side B had no concave portions.

[0057] Example 2

[0058] In the third pass, 84 dtex / 72f circular cross-section, fully matte PET DTY (TiO2 content 2.5 wt%) was used as yarn 1, and in the other passes, 114 dtex / 36f circular cross-section, fully matte PET DTY (TiO2 content 2.5 wt%) was used as yarn 2. The knitted fabrics of the present invention were produced in the same manner as in Example 1. Parameters are detailed in Tables 1 and 2. The resulting knitted fabrics had two longitudinal cross-sectional configurations: in longitudinal cross-sectional configuration 1, side A had no concave portions and side B had continuous concave portions; in longitudinal cross-sectional configuration 2, side A had discontinuous concave portions and side B had no concave portions.

[0059] Example 3

[0060] On a 24G double-sided circular knitting machine, a circular, fully matte PET DTY yarn (TiO2 content: 2.5 wt%) with a 114 dtex / 72 f yarn was used as yarn 3, and a circular, fully matte PET DTY yarn (TiO2 content: 2.5 wt%) with a 144 dtex / 72 f yarn was used as yarn 2 (TiO2 content: 2.5 wt%) in the other knitting machines. The knitted fabrics of the present invention were produced using the same procedures as in Example 1. Parameters are detailed in Tables 1 and 2. The resulting knitted fabrics had two longitudinal cross-sectional configurations: longitudinal cross-sectional configuration 1 had no concave portions on side A and continuous concave portions on side B, and longitudinal cross-sectional configuration 2 had discontinuous concave portions on side A and no concave portions on side B.

[0061] Example 4

[0062] Weaving was performed using stitch 2. Specifically, based on stitch 1, the first loop in the sixth loop (counted from the left) was converted into a floating loop. The remaining knitting procedures were the same as in Example 1, producing the knitted fabric of the present invention. Parameters are detailed in Tables 1 and 2. The resulting knitted fabric had two longitudinal cross-sectional configurations: in longitudinal cross-sectional configuration 1, side A had no concave portions and side B had continuous concave portions; in longitudinal cross-sectional configuration 2, side A had discontinuous concave portions and side B had no concave portions.

[0063] Example 5

[0064] Weaving was performed using weave 3, specifically repeating weave 1 21 times to form weaves 1 to 21, and weaves 2 to 6 to form weaves 22 to 26, i.e., 26 weaves constituted a complete weave. Yarn 1 (TiO2 content: 2.5 wt%) was a 25 dtex / 12f circular cross-section, fully matte PET DTY yarn (TiO2 content: 2.5 wt%), used in weave 23. Yarn 2 (TiO2 content: 2.5 wt%) was a 65 dtex / 72f circular cross-section, fully matte PET DTY yarn (TiO2 content: 2.5 wt%), used in the other weaves. The remaining steps were the same as in Example 1, yielding the knitted fabric of the present invention. Parameters are detailed in Tables 1 and 2. The resulting knitted fabric had two longitudinal cross-sectional configurations: in longitudinal cross-section 1, side A had no concave portions and side B had continuous concave portions; in longitudinal cross-section 2, side A had discontinuous concave portions and side B had no concave portions.

[0065] Example 6

[0066] Knitting was performed using stitch 4, with 18 stitches forming a complete stitch. Specifically, stitch 1 of stitch 1 was repeated 13 times to form stitches 1 to 13, and stitches 2 to 6 of stitch 1 were used to form stitches 14 to 18. The remaining steps were the same as in Example 5 to produce the knitted fabric of the present invention. Parameters are detailed in Tables 1 and 2. The resulting knitted fabric had two longitudinal cross-sectional configurations: in longitudinal cross-sectional configuration 1, side A had no concave portions and side B had continuous concave portions; in longitudinal cross-sectional configuration 2, side A had discontinuous concave portions and side B had no concave portions.

[0067] Example 7

[0068] Weaving was performed using stitch 5, with 38 stitches forming a complete stitch. Specifically, stitches 3 to 6 of stitch 1 were repeated nine times as a loop to form stitches 3 to 38 of stitch 4. The remaining conditions were the same as in Example 5 to produce the knitted fabric of the present invention. Parameters are detailed in Tables 1 and 2. The resulting knitted fabric had two longitudinal cross-sectional configurations: in longitudinal cross-sectional configuration 1, side A had no concave portions and side B had continuous concave portions; in longitudinal cross-sectional configuration 2, side A had discontinuous concave portions and side B had no concave portions.

[0069] Example 8

[0070] Weaving was performed using stitch 6, with 18 stitches forming a complete stitch. Specifically, stitches 3 to 6 of stitch 1 were repeated four times as a loop to form stitches 3 to 18 of stitch 4. The remaining conditions were the same as in Example 5 to produce the knitted fabric of the present invention. Parameters are detailed in Tables 1 and 2. The resulting knitted fabric had two longitudinal cross-sectional configurations: in longitudinal cross-sectional configuration 1, side A had no concave portions and side B had continuous concave portions; in longitudinal cross-sectional configuration 2, side A had discontinuous concave portions and side B had no concave portions.

[0071] Example 9

[0072] The knitted fabric of the present invention was produced by knitting using weave 7 shown in FIG3 , with six weaves forming a complete weave. The remaining parameters were the same as in Example 1. Parameters are detailed in Tables 1 and 2. The resulting knitted fabric had two longitudinal cross-sectional configurations: in longitudinal cross-section 1, side A had no concave portions and side B had discontinuous concave portions; in longitudinal cross-section 2, side A had discontinuous concave portions and side B had no concave portions.

[0073] Example 10

[0074] The knitted fabric of the present invention was produced by knitting the weave 8 shown in FIG4 , with six weaves forming a complete weave. The remaining parameters were the same as in Example 7. Parameters are detailed in Tables 1 and 2. The resulting knitted fabric had two longitudinal cross-sectional configurations: in longitudinal cross-section 1, side A had no concave portions and side B had continuous concave portions; in longitudinal cross-section 2, side A had discontinuous concave portions and side B had no concave portions.

[0075] Example 11

[0076] The knitted fabric of the present invention was produced using the weave 9 shown in FIG5 . Yarn 1 (TiO2 content: 2.5 wt%) was made of 54 dtex / 72f circular cross-section, fully matte PET DTY in the fourth weave; yarn 2 (TiO2 content: 2.5 wt%) was made of 84 dtex / 36f circular cross-section, fully matte PET DTY in the first, second, and third weaves; and yarn 3 (ZnO content: 2.5 wt%) was made of 84 dtex / 36f circular cross-section, fully matte PET DTY in the fifth and sixth weaves. The remaining conditions were the same as in Example 1. Parameters are detailed in Tables 1 and 2. The resulting knitted fabric had two longitudinal cross-sectional configurations: in longitudinal cross-sectional configuration 1, side A had no concave portions and side B had discontinuous concave portions; and in longitudinal cross-sectional configuration 2, side A had discontinuous concave portions and side B had no concave portions.

[0077] Example 12

[0078] The knitted fabric of the present invention was produced using weave 10, specifically, by removing the fourth and eighth columns from left to right from weave 9. Specifically, the number of wales in a complete weave was reduced from 8 to 6. The remaining parameters were the same as in Example 11. Parameters are detailed in Tables 1 and 2. The resulting knitted fabric had two longitudinal cross-sectional configurations: longitudinal cross-sectional configuration 1, in which side A had no concave portions and side B had discontinuous concave portions; longitudinal cross-sectional configuration 2, in which side A had discontinuous concave portions and side B had no concave portions.

[0079] Example 13

[0080] Knitting was performed using weave 1, with 29 dtex / 24f circular cross-section, fully matte PET DTY (TiO2 content 2.5 wt%) used as yarn 1 in the third knitting process, and 54 dtex / 36f circular cross-section, fully matte PET DTY (TiO2 content 2.5 wt%) used as yarn 2 in the other knitting processes. The knitted fabrics of the present invention were produced using the same procedures as in Example 1. Parameters are detailed in Tables 1 and 2. The resulting knitted fabrics had two longitudinal cross-sectional configurations: in longitudinal cross-sectional configuration 1, side A had no concave portions and side B had continuous concave portions; in longitudinal cross-sectional configuration 2, side A had discontinuous concave portions and side B had no concave portions.

[0081] Example 14

[0082] Knitting was performed using weave 1, with 29 dtex / 12f circular cross-section, fully matte PET DTY (TiO2 content 2.5 wt%) used as yarn 1 in the third knitting process, and 135 dtex / 72f circular cross-section, fully matte PET DTY (TiO2 content 2.5 wt%) used as yarn 2 in the other knitting processes. The knitted fabrics of the present invention were produced in the same manner as in Example 1. Parameters are detailed in Tables 1 and 2. The resulting knitted fabrics had two longitudinal cross-sectional configurations: in longitudinal cross-sectional configuration 1, side A had no concave portions and side B had continuous concave portions; in longitudinal cross-sectional configuration 2, side A had discontinuous concave portions and side B had no concave portions.

[0083] Example 15

[0084] In the third pass, a 29 dtex / 12f round-cross-section, fully matte PET DTY yarn (TiO2 content: 2.5 wt%) was used as yarn 1, and in the other passes, a 129 dtex / 72f round-cross-section, fully matte PET DTY yarn (TiO2 content: 2.5 wt%) was used as yarn 2. The knitted fabrics of the present invention were produced using the same procedures as in Example 14. Parameters are detailed in Tables 1 and 2. The resulting knitted fabrics had two longitudinal cross-sectional configurations: longitudinal cross-sectional configuration 1 had no concave portions on side A and discontinuous concave portions on side B, and longitudinal cross-sectional configuration 2 had discontinuous concave portions on side A and no concave portions on side B.

[0085] Example 16

[0086] The knitted fabric of the present invention was produced using the weave 11 shown in FIG6 , with a complete weave consisting of seven weaves. Yarn 1 (TiO2 content: 2.5 wt%) was made of 54 dtex / 72f circular cross-section, fully matte PET DTY yarn in weaves 1 through 4, and yarn 4 (TiO2 content: 2.0 wt%) was made of 84 dtex / 36f circular cross-section, fully matte PET DTY yarn in weaves 5 through 7. The remaining conditions were the same as in Example 1. Parameters are detailed in Tables 1 and 2. The resulting knitted fabric had two longitudinal cross-sectional configurations: in longitudinal cross-section 1, side A had no concave portions and side B had discontinuous concave portions; and in longitudinal cross-section 2, side A had discontinuous concave portions and side B had no concave portions.

[0087] Example 17

[0088] In yarns 1, 4, and 5, 54 dtex / 72f circular cross-section, fully matte PET DTY (TiO2 content: 2.5 wt%) was used as yarn 1, and in yarns 2, 3, 6, and 7, 84 dtex / 36f circular cross-section, fully matte PET DTY (TiO2 content: 2.0 wt%) was used as yarn 4. The remaining conditions were the same as in Example 16 to produce the knitted fabrics of the present invention. Parameters are detailed in Tables 1 and 2. The resulting knitted fabrics had two longitudinal cross-sectional configurations: longitudinal cross-sectional configuration 1 had no concave portions on side A and discontinuous concave portions on side B, and longitudinal cross-sectional configuration 2 had discontinuous concave portions on side A and no concave portions on side B.

[0089] Example 18

[0090] On an E22 double-faced raschel machine, knitting was performed using the weave 12 and five guide bars shown in FIG7 . 84 dtex / 72f full-dull PET DTY yarn (TiO2 content 2.5 wt%) was used throughout. The threading pattern was GB1: 2 threaded, 2 unthreaded; GB2: 1 threaded, 2 unthreaded, 1 threaded; GB3: 3 unthreaded, 1 threaded; GB4: 1 unthreaded, 2 threaded, 1 unthreaded; and GB5: 2 unthreaded, 2 threaded. The remaining yarns were the same as in Example 1. The knitted fabric of the present invention was produced. Parameters are detailed in Table 3. The resulting knitted fabric had a single longitudinal cross-sectional morphology, with both sides A and B having discontinuous concave portions.

[0091] Example 19

[0092] A knitted fabric of the present invention was obtained by using weave 13, specifically, weaving weave 12 with an additional guide bar GB6. GB6 used the same weave as GB1 and GB5. The threading patterns were as follows: GB1 (2 threads, 2 holes) × 5, GB2 (1 thread, 2 holes, 1 thread) × 5, GB3 (3 holes, 1 thread) × 5, GB4 (1 hole, 2 threads, 1 hole) × 5, GB5 (2 holes, 2 threads) × 5, and GB6 (15 threads, 1 hole, 3 threads, 1 hole). The remaining yarns were the same as in Example 18. Parameters are detailed in Table 3. The resulting knitted fabric had only one longitudinal cross-sectional shape, with both sides A and B having discontinuous concave portions.

[0093] Example 20

[0094] Using weave 14, specifically, weaving with six weave bars, GB6, in addition to weave 12, GB6 employs the same weave as GB1 and GB5, with a threading pattern of 3 open and 1 threaded. The remaining yarns are the same as in Example 18, producing a knitted fabric of the present invention. Parameters are detailed in Table 3. The resulting knitted fabric has a single longitudinal cross-sectional shape, with both sides A and B having discontinuous concave portions.

[0095] Example 21

[0096] A knitted fabric of the present invention was prepared using 54 dtex / 72 f fully matte PET DTY yarn (TiO2 content 2.5 wt%), with the same parameters as in Example 18. Parameters are shown in Table 3. The resulting knitted fabric had only one longitudinal cross-sectional morphology, with both sides A and B having discontinuous concave portions.

[0097] Example 22

[0098] Using weave 15, specifically, weaving with six guide bars based on weave 12, GB6 used the same weave as GB1 and GB5, with the threading cycle increased from 4 to 20: GB1: (2 threads, 2 gaps) × 5, GB2: (1 thread, 2 gaps, 1 thread) × 5, GB3: (3 gaps, 1 thread) × 5, GB4: (1 gap, 2 threads, 1 gap) × 5, GB5: (2 gaps, 2 threads) × 5, and GB6: 17 threads, 3 gaps. The remaining conditions were the same as in Example 18 to produce a knitted fabric of the present invention. Parameters are detailed in Table 3. The resulting knitted fabric had only one longitudinal cross-sectional shape, with both sides A and B having discontinuous concave portions.

[0099] Comparative Example 1

[0100] Knitted fabrics were produced on a 32G double-sided weft knitting machine using weave 1. Yarn 1 was a 24 dtex / 24f round-cross-section, fully matte PET FDY (TiO2 content 2.5 wt%) yarn in the third pass, and yarn 2 was a 54 dtex / 72f round-cross-section, fully matte PET DTY (TiO2 content 2.5 wt%) yarn in the remaining passes. The remaining conditions were the same as in Example 1. Parameters are detailed in Tables 1 and 2. The resulting knitted fabrics had two longitudinal cross-sectional morphologies: longitudinal cross-sectional 1 had no concave portions on side A and continuous concave portions on side B; longitudinal cross-sectional 2 had discontinuous concave portions on side A and no concave portions on side B.

[0101] Comparative Example 2

[0102] The specific threading method was GB4: 1 threaded, 2 open, 1 threaded, and GB5: 2 threaded, 2 open. The rest of the yarn was the same as in Example 18 to produce a knitted fabric. Parameters are detailed in Table 3. The resulting knitted fabric had only one longitudinal cross-sectional shape, with both sides A and B having discontinuous concave portions.

[0103] Table 1

[0104] Table 2

[0105] Table 3

[0106] According to Table 1, Table 2 and Table 3,

[0107] (1) It can be seen from Examples 1 and 4 that, under the same conditions, the knitted fabrics with recesses located in different longitudinal rows have comparable air permeabilities to the knitted fabrics with recesses located in the same longitudinal row, but the UPF is significantly higher than the latter, that is, the former has significantly better UV protection than the latter.

[0108] (2) It can be seen from Example 6 and Example 5 that, under the same conditions, the UPF of the knitted fabric with an A surface coverage a of 6% is comparable to that of the knitted fabric with an A surface coverage a of 4%, and the air permeability of the former is higher than that of the latter, that is, the UV protection of the two is comparable, and the air permeability of the former is better than that of the latter.

[0109] (3) It can be seen from Example 12 and Example 11 that, under the same conditions, the knitted fabric with a concave width of 3 longitudinal rows on both sides A and B is comparable to the knitted fabric with a concave width of 4 longitudinal rows on both sides A and B. However, the UPF of the two is significantly higher than that of the latter, that is, the UV protection of the former is significantly better than that of the latter.

[0110] (4) It can be seen from Example 1 and Example 13 that, under the same conditions, the knitted fabric with a fineness difference of 30 dtex between coil rows has a higher air permeability and UPF than the knitted fabric with a fineness difference of 25 dtex between coil rows, that is, the air permeability and UV protection of the former are better than those of the latter.

[0111] (5) It can be seen from Example 15 and Example 14 that, under the same conditions, the knitted fabric with a fineness difference of 100 dtex between the horizontal rows and the knitted fabric with a fineness difference of 106 dtex between the horizontal rows have similar air permeability, but the UPF of the former is significantly higher than that of the latter, that is, the UV protection of the former is significantly better than that of the latter.

[0112] (6) It can be seen from Example 19 and Example 22 that, under the same conditions, the knitted fabric with a+b of 60 and |ab| of 50 has higher air permeability and UPF than the knitted fabric with a+b of 58 and |ab| of 52, that is, the air permeability and UV protection of the former are better than those of the latter.

[0113] (7) It can be seen from Comparative Example 1 and Example 1 that, under the same conditions, the knitted fabric with a concave portion (h1+h2) / h of 0.35 has a much lower air permeability than the knitted fabric with a concave portion (h1+h2) / h of 0.45, that is, the air permeability of the former is very poor.

[0114] (8) From Comparative Example 2 and Example 18, it can be seen that under the same conditions, the knitted fabric with a concave portion (h1+h2) / h of 2.00 and h1 / h of 1.00 is compared with the knitted fabric with a concave portion (h1+h2) / h of 1.20 and h1 / h of 0.60, although the former has a ventilation capacity of 248cm3 / (cm 2 ·s), but the UPF is very low, that is, the former has poor UV protection.

Claims

1. Anti-ultraviolet knitted fabric, woven from double-sided tissue, its characteristics are: The knitted fabric has an A side and a B side, a cross-sectional height of h, a concave depth of the A side on the cross-section of h1, and a concave depth of the B side of h2, h, h1 and h2 satisfy the following formula: 0.40<(h1+h2) / h≤1.50, 0.20<h1 / h≤0.75, and the UPF value of the knitted fabric is above 30.

2. The UV-proof knitted fabric according to claim 1, characterized in that: The projection A' of the concave portion of surface A on surface B and the concave portion of surface B are located in different longitudinal rows.

3. The anti-ultraviolet knitted fabric according to claim 2, characterized in that: The knitted fabric has two longitudinal cross-sectional shapes. In longitudinal cross-sectional shape 1, surface A has no concave portion and surface B has continuous concave portion. In longitudinal cross-sectional shape 2, surface A has discontinuous concave portion and surface B has no concave portion.

4. The anti-ultraviolet knitted fabric according to claim 2, characterized in that: The knitted fabric has two longitudinal cross-sectional shapes. In longitudinal cross-sectional shape 1, surface A has no concave portion and surface B has discontinuous concave portion. In longitudinal cross-sectional shape 2, surface A has discontinuous concave portion and surface B has no concave portion.

5. The anti-ultraviolet knitted fabric according to claim 3, characterized in that: In a complete tissue, the coverage rate a of the concave portion of the A surface is 5% to 30%, and the coverage rate b of the concave portion of the B surface is 40% to 60%.

6. The anti-ultraviolet knitted fabric according to claim 3 or 4, characterized in that: The width W1 of the concave portion on the A side and the width W2 of the concave portion on the B side are both less than or equal to 3 longitudinal rows.

7. The anti-ultraviolet knitted fabric according to claim 3 or 4, characterized in that: In a complete structure, there is a fineness difference between at least one row of stitches having a loop structure and other rows of stitches, and the fineness difference is 30 to 100 dtex.

8. The anti-ultraviolet knitted fabric according to claim 1, characterized in that: The knitted fabric has only one longitudinal cross-sectional shape, and both the A side and the B side have discontinuous concave portions.

9. The anti-ultraviolet knitted fabric according to claim 8, characterized in that: In a complete tissue, the coverage rate a of the concave portion of the A surface and the coverage rate b of the concave portion of the B surface satisfy the following relationship: 60%≤a+b≤110%, 0≤|ab|≤50%.

10. The UV-proof knitted fabric according to claim 3, 4 or 8, characterized in that: The content of the anti-ultraviolet yarn in the fabric is more than 50 weight percent, and the anti-ultraviolet yarn is a yarn with an inorganic particle content of more than 2.2 weight percent.

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