High-strength soft degradable wet spunlace material and preparation method thereof

Abstract

The invention belongs to the technical field of non-woven materials, and particularly relates to a high-strength soft degradable wet spunlace material and a preparation method thereof.The mass per unit area of the wet spunlace material is 40 g / m < 2 >-100 g / m < 2 >, the wet spunlace material is composed of plant pulp and regenerated cellulose fibers, the mass proportion of the regenerated cellulose fibers is larger than or equal to 30%, and the balance is the plant pulp; the crushed fibers in the regenerated cellulose fibers account for 10-40% of the total mass of the fibers. According to the invention, most degradable product leftover materials can be used as raw materials of the disintegrating fibers, so that the material utilization rate is greatly improved, the waste treatment cost is reduced, and the cost is effectively reduced on the premise of ensuring high strength and high softness of the product, so that the product has competitiveness.

Description

Technical Field

[0001] The invention relates to the technical field of nonwoven materials, and in particular to a high-strength, soft and degradable wet-process spunlace material and a preparation method thereof. Background Art

[0002] Degradable wet spunlace materials are usually composed of plant pulp and regenerated cellulose fibers. Considering the cost and performance of plant pulp, the plant pulp commonly used for wet spunlace includes softwood pulp, hardwood pulp and bamboo pulp. Among them, hardwood pulp is the shortest, with an average length of about 1mm, bamboo pulp fiber has an average length of 1-2mm, and softwood pulp is longer, with an average length of 2-2mm; commonly used regenerated cellulose fibers include viscose fiber and lyocell fiber. The fiber materials are uniform in length and can be customized, but the length is limited to less than 20mm due to the wet molding process.

[0003] Hydroentanglement is a technology that uses high-pressure water jets to continuously spray the fiber web. This technology uses high-pressure fine water jets to penetrate the fiber web, causing the fibers to intersperse, entangle and embrace in different directions, thereby enhancing the physical properties of the fiber web. Due to the low length and aspect ratio of plant pulp fibers, the entangled network formed after hydroentanglement is not strong enough, and more cellulose fibers are needed to improve the strength of the material. At the same time, due to the lower fineness of cellulose fibers, the material will be softer when the fiber ratio increases.

[0004] Compared with plant pulp, the cost of regenerated cellulose fiber is much higher. Simply increasing the proportion of regenerated cellulose fiber to increase the strength and softness of the material is not economical. Summary of the invention

[0005] The purpose of the present invention is to address the shortcomings of the prior art, by crushing clean and degradable product scraps into crushed fibers, mixing them with primary regenerated cellulose fibers, thereby solving the problem of high cost of existing high-strength, soft, degradable wet-process spunlace materials, and proposing a high-strength, soft, degradable wet-process spunlace material and a preparation method.

[0006] In order to achieve the above-mentioned invention object, the technical solution provided by the present invention is:

[0007] In the first aspect, the present invention provides a high-strength, soft, degradable wet-laid spunlace material, wherein the wet-laid spunlace material has a unit area mass of 40 g / m 2 ~100g / m 2 , consisting of plant pulp and regenerated cellulose fibers, wherein the mass proportion of the regenerated cellulose fibers is greater than or equal to 30%, and the remainder is plant pulp; the fragmented fibers in the regenerated cellulose fibers account for 10% to 40% of the total fiber mass.

[0008] The above technical solution is that when the regenerated cellulose fiber is less than 30%, the high-strength, soft, degradable wet-process spunlace material prepared has low strength and poor softness. When the shredded fiber accounts for less than 10% of the total fiber mass, the dosage is too low and has little effect on reducing costs; and when the shredded fiber accounts for more than 40% of the total fiber mass, the high-strength, soft, degradable wet-process spunlace material prepared has poor overall uniformity, which has a significant negative impact on the strength and softness of the material.

[0009] Preferably, the shredded fibers are obtained by shredding leftover materials of degradable products, and have an average length of 3 to 6 mm.

[0010] The above technical solution is that: since the length of the shredded fiber produced by the shredder is irregular, only upper and lower limits are imposed; when the length of the shredded fiber is less than 3 mm, the length is too short and the effect of increasing the strength cannot be achieved; and when the length of the shredded fiber is greater than 6 mm, the length is too long and the uniformity of the material is affected;

[0011] Preferably, the degradable product for disintegration is a wet dispersible material.

[0012] On the other hand, the present invention provides a method for preparing a high-strength, soft and degradable wet-process spunlace material, comprising the following steps:

[0013] 1) Preparation of plant pulp slurry: feeding the plant pulp into a hydraulic pulper and stirring the pulper to form plant pulp slurry;

[0014] 2) Preparation of regenerated cellulose fiber slurry: adding regenerated cellulose fibers into a stirring tank, stirring to disperse the fibers, and preparing regenerated cellulose fiber slurry;

[0015] 3) Preparation of fiber slurry: Feed the leftovers of biodegradable products into a slurry crusher to make slurry with an area of ​​4 to 9 mm 2 The fiber fragments are sent to a hydraulic pulper to be made into a broken fiber slurry, the broken fiber slurry is firstly subjected to a decomposition treatment to remove the super-long fibers, and then subjected to a screening treatment to remove the cotton blocks and cotton knots, and finally sent to a stock preparation pool for standby use; the super-long fibers are greater than 12 mm in length;

[0016] 4) Fiber web forming: plant pulp slurry, regenerated cellulose fiber slurry and shredded fiber slurry are mixed in proportion to form a mixed slurry, which is then screened to remove cotton blocks and neps and then sent to the inclined net forming system to form a wet fiber web after inclined net forming;

[0017] 5) Fiber web reinforcement: The front and back sides of the dehydrated fiber web are subjected to multiple water spunlace processes to remove excess water from the material. After drying and rolling, a high-strength, soft, and biodegradable wet-process water-spunlace material is produced.

[0018] Preferably, in step 1), the plant pulp is one or more combinations of wood pulp, bamboo pulp, cotton pulp and hemp pulp; further, the plant pulp slurry concentration is 0.1wt% to 2wt%;

[0019] Preferably, in step 2), the regenerated cellulose fiber is one or more combinations of viscose, lyocell and modal; further, the concentration of the regenerated cellulose fiber slurry is 0.1wt% to 1.5wt%;

[0020] Preferably, in step 3), the shredded fibers are derived from leftovers of degradable products, wherein the fiber types may be one or more combinations of viscose, lyocell, modal, natural fiber cellulose fibers, etc.; further, the concentration of the shredded fiber slurry is 0.1wt% to 0.7wt%;

[0021] Preferably, in step 4), the concentration of the mixed slurry is 0.5wt% to 1.5wt%;

[0022] Preferably, in step 5), the spunlacing process is: 4 spunlacings on the front side and 2 spunlacings on the back side;

[0023] Compared with the prior art, the present invention has the following beneficial effects:

[0024] In the present invention, the shredded fibers can use most of the leftovers of biodegradable products as raw materials, which greatly improves the material utilization rate and reduces the cost of waste disposal. Under the premise of ensuring the high strength and high softness of the product, the cost is effectively reduced to make it competitive. DETAILED DESCRIPTION

[0025] The present invention will be further described below in conjunction with the embodiments.

[0026] Overall embodiment

[0027] A high-strength, soft and biodegradable wet-process spunlace material is composed of plant pulp and regenerated cellulose fibers; the mass proportion of the regenerated cellulose fibers is greater than or equal to 30%, and the remainder is plant pulp; the fragmented fibers in the regenerated cellulose fibers account for 10% to 40% of the total fiber mass.

[0028] As a specific embodiment, the regenerated cellulose fiber is one or more combinations of viscose, lyocell and modal; and the regenerated cellulose fiber has a specification of 0.5 dtex to 2 dtex and a length of 5 mm to 15 mm;

[0029] As a specific implementation, the plant pulp is one or more combinations of wood pulp, bamboo pulp, cotton pulp and hemp pulp;

[0030] As a specific embodiment, the shredded fibers are derived from leftovers of degradable products, wherein the fiber types may be one or more combinations of viscose, lyocell, modal, natural fiber cellulose fiber, etc.; and the average length of the shredded fibers is 3 to 6 mm;

[0031] As a specific implementation, the high-strength, soft, degradable wet-laid spunlace material has a unit area mass of 40 g / m 2 ~100g / m 2 ;

[0032] A method for preparing a high-strength, soft and degradable wet-process spunlace material comprises the following steps:

[0033] (1) feeding the plant pulp into a hydraulic pulper and stirring the pulper to form a plant pulp slurry;

[0034] (2) adding regenerated cellulose fibers into a stirring tank and stirring to disperse the fibers to prepare a fiber slurry;

[0035] (3) Feed the degradable product scraps into a crusher to make a 4-9mm 2 The fiber fragments are sent to a hydraulic pulper to be made into a broken fiber slurry, the broken fiber slurry is firstly subjected to a decomposition treatment to remove the super-long fibers, and then subjected to a screening treatment to remove the cotton blocks and cotton knots, and finally sent to a stock preparation pool for standby use; the super-long fibers are greater than 12 mm in length;

[0036] (4) mixing plant pulp slurry, regenerated cellulose fiber slurry and shredded fiber slurry in proportion to form a mixed slurry, and then screening to remove cotton blocks and cotton knots and then feeding it into an inclined screen forming system, and then forming it into a wet fiber web through an inclined screen;

[0037] (5) The front and back sides of the dehydrated fiber web are subjected to multiple water spunlaces to remove excess water from the material, and then the material is dried and rolled into a high-strength, soft, and biodegradable wet-process water-spunlace material.

[0038] As a specific implementation, in step (1), the concentration of the plant pulp slurry is 0.1wt% to 2wt%;

[0039] As a specific embodiment, in step (2), the fiber slurry is 0.1wt% to 1.5wt%;

[0040] As a specific embodiment, in step (3), the concentration of the shredded fiber slurry is 0.1wt% to 0.7wt%;

[0041] As a specific embodiment, in step (4), the concentration of the mixed slurry is 0.5wt% to 1.5wt%;

[0042] As a specific implementation, in step (5), the spunlace process is: 4 spunlaces on the front side and 2 spunlaces on the back side.

[0043] Embodiment 1:

[0044] A high-strength, soft, biodegradable wet-laid spunlace material with a mass per unit area of ​​55g / m 2 , the material is composed of plant pulp and regenerated cellulose fibers; wherein the proportion of the regenerated cellulose fibers is 40%, and the proportion of the plant pulp is 60%; further, the broken fibers in the regenerated cellulose fibers account for 25% of the total fiber mass;

[0045] As a specific embodiment, the regenerated cellulose fiber is 100% lyocell fiber; the fiber linear density is 0.9 dtex, and the length is 8 mm;

[0046] As a specific embodiment, the shredded fibers are derived from the leftovers of degradable products containing 100% viscose fibers, with a fiber linear density of 1.67 dtex and an average fiber length of 4.2 mm;

[0047] As a specific implementation, the plant pulp is coniferous wood pulp;

[0048] After the above preparation method, the plant pulp slurry concentration is 1.1wt%; the fiber slurry concentration is 1.2wt%; the area of ​​the broken fiber fragments is 5mm 2 ~6mm 2 , the concentration of the fiber slurry is 0.4wt%; the concentration of the mixed slurry is 1.06wt%;

[0049] The 4-pass water spunlace pressures on the front side are 35 bar, 60 bar, 65 bar and 65 bar respectively, and the 2-pass water spunlace pressures on the back side are 70 bar and 65 bar respectively. The production line speed is 125 m / min.

[0050] Embodiment 2:

[0051] Comparative Example 1, the regenerated cellulose fiber is a lyocell fiber with a fiber fineness of 2 dtex and a length of 8 mm; other conditions remain the same;

[0052] Embodiment 3:

[0053] Comparative Example 1, the regenerated cellulose fiber is 100% viscose fiber; other conditions remain the same;

[0054] Comparative Example 1:

[0055] Comparative Example 1, the proportion of regenerated cellulose fiber is set to 10%, the proportion of plant pulp is set to 90%, the crushed fiber in the regenerated cellulose fiber accounts for 25% of the total fiber mass, and other conditions remain the same;

[0056] Comparative Example 2:

[0057] Comparative Example 1, the average length of the shredded fibers was changed to 8.3 mm, and the area of ​​the shredded fiber fragments was 10 mm 2 ~15mm 2 , other conditions remain the same;

[0058] Comparative Example 3:

[0059] Comparative Example 1, the disintegrated fibers in the regenerated cellulose fibers accounted for 60% of the total fiber mass, and other conditions remained the same; Comparative test report

[0060] Test purpose: Test the example materials and comparative example materials, and test the dry breaking strength and softness index of the materials for comparative evaluation.

[0061] Test method:

[0062] (1) Dry breaking strength: the test method is in accordance with GB / T 30133-2013 General Technical Specification for Sanitary Napkin Surface Layer;

[0063] (2) Softness: The test method is in accordance with GB / T 8942-2016 Determination of paper softness

[0064] Test comparison report

[0065]

[0066] Test result evaluation:

[0067] (1) Compared with Example 1, after the linear density of the lyocell fiber in Example 2 is increased from 0.9 dtex to 2.0 dtex, the aspect ratio of the fiber itself is reduced, and the hydroentanglement ability is reduced, resulting in a decrease in the longitudinal and transverse breaking strength of the material.

[0068] (2) Compared with Example 1, the lyocell fiber in the regenerated cellulose in Example 3 is replaced by viscose fiber. Since the entanglement ability of viscose fiber is lower than that of lyocell fiber, the longitudinal and transverse breaking strength of the material is reduced. However, the crystallinity of viscose fiber itself is lower and it is softer than lyocell fiber, so the softness of the material is increased.

[0069] (3) Comparative Example 1: In Comparative Example 1, the proportion of regenerated cellulose fiber is set to 10%. Since the aspect ratio of cellulose fiber is much higher than that of wood pulp, the material is poorly entangled after water jetting, and the breaking strength is greatly reduced. At the same time, since the wood pulp fiber is in the form of a flat ribbon, the contact area between the fibers is large, resulting in a tighter connection of the material due to hydrogen bonds, and the material hardness is greater.

[0070] (4) Compared with Example 1, in Example 2, the average length of the shredded fibers becomes 8.3 mm, and the area of ​​the shredded fiber fragments is 10 mm 2 ~15mm 2 The material uniformity is poor due to the excessive length of the shredded fibers, which ultimately reduces the strength of the material. And due to the flocculation of long fibers, the proportion of wood pulp in some parts of the material is high, and the hardness increases.

[0071] (5) Compared with Example 1, in Comparative Example 3, the shredded fibers in the regenerated cellulose fibers accounted for 60% of the total fiber mass. As the proportion of shredded fibers increased, the uniformity of the material decreased, resulting in a decrease in the strength of the material.

[0072] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the scope disclosed by the present invention should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention shall be based on the protection scope of the claims.

Claims

1. A high-strength, soft and degradable wet-process spunlace material, characterized by: The wet spunlace material has a unit area mass of 40 g / m 2 ~100g / m 2 , consisting of plant pulp and regenerated cellulose fibers, wherein the mass proportion of the regenerated cellulose fibers is greater than or equal to 30%, and the remainder is plant pulp; the fragmented fibers in the regenerated cellulose fibers account for 10% to 40% of the total fiber mass.

2. The high-strength, soft, degradable wet-process spunlace material according to claim 1, characterized in that: The shredded fibers are obtained by shredding the leftover materials of degradable products, and have an average length of 3 to 6 mm.

3. The high-strength, soft, degradable wet-process spunlace material according to claim 2, characterized in that: The degradable product for disintegration is a wet flushable material.

4. A method for preparing the high-strength, soft, degradable wet-process spunlace material according to any one of claims 1 to 3, characterized in that: The steps include: 1) Preparation of plant pulp slurry: feeding the plant pulp into a hydraulic pulper and stirring the pulper to form plant pulp slurry; 2) Preparation of regenerated cellulose fiber slurry: adding regenerated cellulose fibers into a stirring tank, stirring to disperse the fibers, and preparing regenerated cellulose fiber slurry; 3) Preparation of fiber slurry: Feed the leftovers of biodegradable products into a slurry crusher to make slurry with an area of ​​4 to 9 mm 2 The fiber fragments are sent to a hydraulic pulper to be made into a broken fiber slurry, the broken fiber slurry is firstly subjected to a decomposition treatment to remove the super-long fibers, and then subjected to a screening treatment to remove the cotton blocks and cotton knots, and finally sent to a stock preparation pool for standby use; the super-long fibers are greater than 12 mm in length; 4) Fiber web forming: plant pulp slurry, regenerated cellulose fiber slurry and shredded fiber slurry are mixed in proportion to form a mixed slurry, which is then screened to remove cotton blocks and neps and then sent to the inclined net forming system to form a wet fiber web after inclined net forming; 5) Fiber web reinforcement: The front and back sides of the dehydrated fiber web are subjected to multiple water spunlace processes to remove excess water from the material. After drying and rolling, a high-strength, soft, and biodegradable wet-process water-spunlace material is produced.

5. The preparation method according to claim 4, characterized in that: In the step 1), the plant pulp is one or more combinations of wood pulp, bamboo pulp, cotton pulp or hemp pulp, and the concentration of the plant pulp slurry is 0.1wt% to 2wt%.

6. The preparation method according to claim 4, characterized in that: In the step 2), the regenerated cellulose fiber is one or more combinations of viscose, lyocell or modal, and the concentration of the regenerated cellulose fiber slurry is 0.1wt% to 1.5wt%.

7. The preparation method according to claim 4, characterized in that: In the step 3), the shredded fibers are derived from leftovers of degradable products, wherein the fiber types are one or more combinations of viscose, lyocell, modal or natural cellulose fibers; and the concentration of the shredded fiber slurry is 0.1wt% to 0.7wt%.

8. The preparation method according to claim 4, characterized in that: In the step 4), the concentration of the mixed slurry is 0.5wt% to 1.5wt%.

9. The preparation method according to claim 4, characterized in that: In the step 5), the spunlace process is: 4 spunlaces on the front side and 2 spunlaces on the back side.

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