CN117867754A - Non-woven fabric capable of being dispersed - Google Patents

Abstract

The invention relates to a flushable non-woven fabric, which comprises natural fibers and viscose fibers which are entangled with each other, wherein the length of the natural fibers is 1.5-3 mm, the length-to-width ratio is 80-160, the wall cavity ratio is greater than or equal to 1, the length of the viscose fibers is 4-10 mm, the viscose fibers account for 20% -25%, and the number ratio of the fibers with the length less than 1mm in the natural fibers account for 4-10%, so that the formed flushable non-woven fabric can realize good flushability and strength and can meet the requirement of service performance through the proportion.

Description

Non-woven fabric capable of being dispersed

Technical Field

The invention relates to a flushable non-woven fabric.

Background

With the rapid development of economy, the pursuit of quality of life has been increasing, and in recent years, nonwoven fabric products (face tissues, makeup removing tissues, cotton soft tissues, etc.) have become an indispensable part of daily life. The non-woven fabric has the advantages of wide raw material sources, various types, soft and fluffy handfeel and the like, and the non-woven fabric gradually develops towards green and environment protection along with the increasing of environmental protection consciousness of consumers.

For this reason, the north american nonwoven industry association (INDA) and european nonwoven association (EDANA) have given the definition of "flushability" in the flushable guide, commonly established in 2008, and thus various flushable nonwoven products and technologies have been proposed in the industry before and after that, such as the document number CN101984177a, entitled: patent literature on flushable degradable wood pulp composite nonwoven fabric suggests that a wood pulp fiber layer of 2-5mm and a nonwoven fiber layer are a nonwoven fabric compounded by hydroentanglement, and has flushability, for example, the literature number is CN108474153a, and the name is: patent literature on a hydrolyzable nonwoven fabric and a method for producing the same shows another flushable nonwoven fabric and a method for producing the same.

And, many research documents in the industry, such as the problems and development directions faced by the flushable wet tissues published in the 2019.11 stage of the paper for daily use, and the like, combined with various prior art and research documents, can find that the industry proposes that longer fibers should be used as much as possible, for example, the fiber length cannot be shorter than 5mm, preferably 5-20mm, as mentioned in the patent document US5384189a, water-soluble non-woven fabric, and the characteristics of softwood pulp fibers are combined, so that the flushable non-woven fabrics all adopt the slurry form of the softwood pulp and viscose fibers at present, but other natural fibers still exist in the market, and the natural fibers still hope to reach the flushable requirement.

For this reason, a new technical solution is needed to solve the above technical problems.

Disclosure of Invention

Therefore, the invention provides a flushable non-woven fabric to solve the technical problems.

The non-woven fabric capable of being scattered comprises natural fibers and viscose fibers which are entangled with each other, wherein the average length of the natural fibers is 1.5-3 mm, the length-to-width ratio is 80-160, the wall cavity ratio is greater than or equal to 1, the length of the viscose fibers is 4-10 mm, the viscose fibers account for 20% -25%, and the number ratio of the fibers with the length less than 1mm in the natural fibers is 4-10%.

Wherein the natural fiber is bamboo pulp fiber.

The viscose fiber is a flat viscose fiber, and the length of the flat viscose fiber is 4-7 mm.

Before forming the flushable non-woven fabric, the natural fibers are firstly subjected to screening treatment, natural fiber raw materials are screened into first sizing agent with the length of less than 1.0mm and second sizing agent with the length of more than 1.0mm, and then the proportion of the first sizing agent and the second sizing agent is adjusted to form mixed sizing agent, so that the fibers with the length of less than 1.0mm in the formed mixed sizing agent account for 4-10% of the quantity of the natural fibers.

Wherein the bamboo pulp fiber is a mixture of at least two kinds of bamboo pulp fibers, the aspect ratio of the mixed bamboo pulp fiber is 80-100, and the wall cavity ratio is 1-3.

Wherein the bamboo pulp fiber is a mixture of phyllostachys pubescens fiber and miscellaneous bamboo fiber, and the proportion of phyllostachys pubescens fiber to miscellaneous bamboo fiber is 50:50-70:30.

Wherein, the bamboo pulp fiber is made of 60 percent phyllostachys pubescens and 40 percent miscellaneous bamboo, and the average fiber length is as follows: 1.72mm, an average aspect ratio of 92, and an average wall cavity ratio of 2.45, wherein the fiber length of less than 1mm is 7.6%.

Wherein, the bamboo pulp fiber is 100% of Cizhu, and the average fiber length is as follows: 1.99mm, an average aspect ratio of 139, and an average wall cavity ratio of 1.9, wherein the fiber length of less than 1mm is 9.6%.

Wherein, the bamboo pulp fiber is 100% phyllostachys pubescens, and the average fiber length is as follows: 1.8mm, an average aspect ratio of 85, and an average wall cavity ratio of 2.1, wherein the fiber length of less than 1mm is 6.5%.

The beneficial effects are that: the invention relates to a flushable non-woven fabric, which comprises natural fibers and viscose fibers which are entangled with each other, wherein the length of the natural fibers is 1.5-3 mm, the length-to-width ratio is 80-160, the wall cavity ratio is greater than or equal to 1, the length of the viscose fibers is 4-10 mm, the viscose fibers account for 20% -25%, and the number ratio of the fibers with the length less than 1mm in the natural fibers account for 4-10%, so that the formed flushable non-woven fabric can realize good flushability and strength and can meet the requirement of service performance through the proportion.

Detailed Description

The invention provides a flushable non-woven fabric which has good water dispersion performance, and can be rapidly flushable under the action of water flow of the environment such as a toilet when being discarded in the environment such as the toilet, thereby avoiding blocking the toilet or a pipeline or reducing the risk of blocking the toilet and the pipeline.

The non-woven fabrics can be formed by intertwining the fibers without the aid of adhesives, and the intertwining can be performed by intertwining the natural fibers with the natural fibers, the natural fibers with the viscose fibers or the viscose fibers.

Wherein the length of the natural fiber is 1.5-3 mm, the length-width ratio is 80-160, the wall cavity ratio is more than or equal to 1, more specifically, the natural fiber is bamboo pulp fiber, such as Ci bamboo, mao bamboo, wood bamboo, green bamboo, phyllostachys pubescens, etc., preferably, the length of the bamboo pulp fiber is 1.6-2.5 mm, for example: 1.6mm, 1.7mm, 1.8mm, 1.9mm, 2.0mm, 2.1mm, 2.2mm, 2.3mm, 2.4mm, 2.5mm, etc., and it is preferable that the wall cavity ratio is 1.2 to 6.5, more preferably 1.6 to 5.0.

Further, the bamboo pulp fiber is a mixture of at least two kinds of bamboo pulp fibers, the aspect ratio of the mixed bamboo pulp fiber is 80-100, and the wall cavity ratio is 1-3.

Further, the bamboo pulp fiber is a mixture of phyllostachys pubescens fiber and miscellaneous bamboo fiber, and the proportion of phyllostachys pubescens fiber to miscellaneous bamboo fiber is 50:50-70:30.

It is understood that the lengths in the following description are all average lengths, the aspect ratio is an average aspect ratio, and the wall cavity ratio is an average wall cavity ratio.

The length of the viscose fiber is 4-10 mm, preferably 4-7 mm, such as 4mm,5mm,6mm,7mm, etc., in this embodiment, the denier of the viscose fiber is preferably below 16 denier, more preferably, the denier of the flat viscose fiber is 5-15 denier, wherein the "denier" is the industrial weight unit called "denier" or "denier", expressed in grams by weight of the 9000m length of the fiber, and reflects the coarseness of the fiber.

Further, the viscose fiber can be a flat viscose fiber or a round viscose fiber, the flat viscose fiber is obtained by dissolving natural fiber in a corresponding solvent and then carrying out wet spinning, and researches show that the bending rigidity of the fiber has an important influence on the entanglement performance of the fiber, the lower the bending rigidity is, the easier the fiber is entangled, and the flat viscose fiber has smaller bending rigidity, so that the flat viscose fiber is easier to be entangled in the fiber processing process, and the entanglement performance of a non-woven material formed by the flat viscose fiber is better when the same energy (such as water needle energy) is applied; in other words, to achieve the same entanglement effect, the flat viscose fiber has a lower entanglement energy than that required for the conventional viscose fiber, and on the other hand, the entanglement obtained by the physical property of the fiber by itself is a frictional cohesion property, which is more easily dispersed by the action of external force in water, unlike the externally added reinforcing energy, so that the nonwoven material processed from the flat viscose fiber has a better water-flushability, i.e., the flat viscose fiber has a better entanglement capability and water-flushability than the circular viscose fiber, and therefore, the viscose fiber is preferably a flat viscose fiber.

In addition, the mass ratio of the viscose fiber to the total fiber is 20-25%.

Further, the viscose fiber comprises a flat viscose fiber and a round viscose fiber, and the ratio of the flat viscose fiber to the prototype viscose fiber is 5:5-9:1.

It will be appreciated that the viscose may comprise lyocell.

In the field of flushable non-woven fabrics, the flushable non-woven fabrics need to meet the requirements of flushable performance and strength at the same time, but the flushable performance and strength are opposite, namely, the higher the strength is, the worse the flushable performance is, the strength is reduced when the flushable performance is improved, in the current research, wood pulp and viscose fiber, especially softwood pulp and viscose fiber are generally adopted as main materials, because the softwood pulp fiber has a relatively longer length (generally more than 3.6mm and even more than 4 mm), the aspect ratio of the softwood pulp is lower, generally less than 80, the wall cavity ratio of the softwood pulp is smaller (generally less than 1), the softwood fiber is longer, the softwood fiber can have more entanglement points with the viscose fiber, the softwood fiber is in a structure with a thin wall cavity because the aspect ratio is low, the softwood pulp is subjected to a water flow action surface and can be easily released from a entangled state and dispersed, thus, the requirements of strength and water scattering performance are met at the same time, the field generally considers that other fibers are difficult or impossible to meet the requirements of water scattering performance and strength at the same time, and the applicant finds that when the conventional thinking is adopted for bamboo pulp fibers, or the fibers mainly comprising long fibers are formed through screening and screening, the fibers are in a slender state, and the wall thickness cavities of the bamboo fibers are small, so that after entanglement of the fibers and viscose fibers, on one hand, the entanglement formed between the fibers is more compact, disordered and the formed bonding points are more, on the other hand, the entanglement forms are not easy to contact under the action of water flow due to the finer relative wood pulp and the small wall thickness cavities, and particularly, when the strength requirements are met under the condition that the fibers are shorter, when the viscose fiber needs to be added or longer viscose fiber is used, the requirements of strength and flushability are not met easily, the applicant further researches find that when a part of short fibers exist in the slender fibers, the short fibers can be entangled with the slender fibers on one hand, the entangled position can be occupied by the short fibers, the entangled position can be occupied by the slender fibers, the elongated fibers can be reduced in the entangled state, on the other hand, the existing part of short fibers are easily separated under the impact of water flow, the pores of the non-woven fabric are increased in the separation process, the flow rate and the pressure of the water flow at the pores are further increased, so that the fibers at the pores are lost along with the water flow, and are disintegrated and dispersed, but when the tiny fibers are in a dry state or are not in the water flow, the non-woven fabric can be kept in an intact state, and the natural fibers with the fiber length of less than 1.0mm account for 4% or more of the natural fibers.

Further, the number ratio of the fibers with the fiber length less than or equal to 1.0mm to the natural fibers is 4-10%, so that the strength and the flushable performance of the flushable non-woven fabric can meet the usable requirements or at least meet the national standard requirements.

Further, before forming the non-woven fabric, the natural fibers are screened, raw material fibers are screened into first sizing agent with the length of less than 1.0mm and second sizing agent with the length of more than 1.0mm, and then the proportion of the first sizing agent and the second sizing agent is adjusted to form mixed sizing agent, so that the number ratio of the fibers with the length of less than 1.0mm in the formed mixed sizing agent to the natural fibers is 4-10%.

Meanwhile, the flushable non-woven fabric of the invention is prepared in the following manner: firstly, preparing natural fibers to form natural fiber slurry, preparing viscose fibers to form viscose fiber slurry, mixing the natural fiber slurry and the viscose fiber slurry according to a proportion to form mixed slurry, forming wet fiber meshes by the mixed slurry in a wet-process net forming mode, transferring the wet fiber meshes to a water-jet net curtain for water-jet reinforcement, and then drying to form the flushable non-woven fabric.

In addition, because the natural fibers used in the present application are more elongated than they are, they are themselves more susceptible to twisting, and relatively lower hydroentangling pressures can be used in the hydroentangling process.

For a clearer description of the hydroentangling pressure, the hydroentangling process will be further described in detail below:

in hydroentanglement, a wet fiber web is laid on a continuously movable hydroentangled curtain and moves in accordance with the movement of the hydroentangled curtain, a high-pressure water jet is sprayed onto the wet fiber web by a hydroentangled nozzle in a direction substantially perpendicular to the wet fiber web so that the jet passes from the surface of the wet fiber web to the bottom surface thereof, and part of fibers are bent, twisted and twisted under the action of the high-pressure water jet to form intertwining, thereby forming a substrate of the flushable nonwoven fabric, and it is understood that the properties of the nonwoven fabric obtained by the hydroentangled jet treatment vary with the parameters such as the weight per unit area of the wet fiber web, the aperture of the nozzle, the number of holes of the nozzle, the passing speed (treatment speed) when the fiber web is treated.

In general, the water flow should be made to have a work load of 0.05 to 0.5 KW/square meter, and if the work load is greater than the upper limit, the entanglement between the fibers is excessive, so that the hydrolyzability thereof is lowered, and at the same time, the wet fiber web may be broken during the hydroentanglement, and at the same time, if the work load is less than the lower limit, the bulkiness thereof is deteriorated.

For this reason, in practice, a plurality of sets of the water jet nozzles are generally adopted, in this embodiment, at least five sets of the water jet nozzles are adopted, the pressures of the plurality of sets of water jet nozzles are increased in steps in sequence, and the pressure of the first set of water jet nozzles located at the upstream of the plurality of sets of water jet nozzles is less than or equal to 50% of the pressure of the most downstream set of water jet nozzles.

Further, such a hydroentanglement process may be applied to only one side surface of the wet fiber web or to both side surfaces simultaneously. For example, a flushable nonwoven fabric having excellent hydrolyzability and wet strength can be obtained by subjecting one side surface of a wet fiber web to a hydraulic jet treatment of several times of 0.05 to 0.5 KW/square meter. Or the two sides of the wet fiber net sheet, namely the bottom surface and the surface of the wet fiber net sheet are respectively subjected to a plurality of hydraulic spraying treatments of 0.05-0.5 KW per square meter.

The flushable nonwoven fabric of the present application is further illustrated by the following specific examples:

example 1:

natural fiber: 60% phyllostachys pubescens+40% miscellaneous bamboo, average fiber length: 1.72mm, an average aspect ratio of 92, an average wall cavity ratio of 2.45, wherein fibers having a fiber length of less than 1mm account for 6.6%;

viscose fiber: morphology: flat, 5mm long, 25% viscose.

Example 2:

natural fiber: 100% of Ci bamboo, average fiber length: 1.99mm, an average aspect ratio of 139, an average wall cavity ratio of 1.9, wherein fibers having a fiber length of less than 1mm account for 7.6%;

viscose fiber: morphology: round, 5mm long, and 20% of viscose fiber.

Example 3:

natural fiber: 100% phyllostachys pubescens, average fiber length: 1.8mm, an average aspect ratio of 85, an average wall cavity ratio of 2.1, wherein fibers having a fiber length of less than 1mm account for 4.5%;

viscose fiber: morphology: flat, 5mm long, 25% viscose.

Comparative example 1:

natural fiber: 100% of Ci bamboo, average fiber length: 2.6mm, an average aspect ratio of 189, an average wall cavity ratio of 2.2, wherein fibers having a fiber length of less than 1mm account for 0.1%;

viscose fiber: morphology: round, 5mm long, and 20% of viscose fiber.

In this example, the natural fibers were subjected to a pretreatment of screening to remove natural fibers having a length of 1mm or less.

Comparative example 2:

natural fiber: eucalyptus, average fiber length: 1.05mm, an average aspect ratio of 66, an average wall-cavity ratio of 0.75;

viscose fiber: morphology: circular, 12mm long, and 30% of viscose fiber.

Comparative example 3:

natural fiber: masson pine, average fiber length: 3.7mm, an average aspect ratio of 72, an average wall-to-cavity ratio of 0.64;

viscose fiber: the length is 8mm, and the viscose accounts for 50 percent.

Comparative example 3:

natural fiber: masson pine, average fiber length: 3.9mm, average aspect ratio 68, average wall cavity ratio 0.7;

viscose fiber: the length is 10mm, and the viscose accounts for 30 percent.

The basis weight, dry transverse tension (dry-CDT), dry longitudinal tension (dry-MDT), wet transverse tension (wet-CDT), wet longitudinal tension (wet-MDT) and dispersibility tests were carried out on the above examples and comparative examples, and the following table shows the requirements for flushable nonwoven fabrics in GB/T41244-2022 flushable spunlaced nonwoven materials and articles:

wherein,

the test method of the longitudinal dry tension and the transverse dry tension refers to the test method of the GB/T24218.3-2010 textile non-woven fabric part 3: determination of breaking Strength and elongation at break in the test method of 50mm sample width, 100mm grip distance, 100mm/min stretching speed.

The longitudinal wet strength and the transverse wet strength are referred to by a 5.2 test method of a flushability test method and an evaluation of a GB/T40181-2021 disposable sanitary nonwoven material, wherein the width of a sample is 50mm, the clamping distance is 100mm, and the stretching speed is 100mm/min.

The water dispersibility test is carried out by adopting the test step of the 7 shaking box decomposition test in GB/T40181-2021 test method and evaluation for the flushability of the disposable sanitary nonwoven material.

From the comparison, examples 1-3 are still weaker in terms of strength than comparative examples 3, 4 of the prior art, but have been able to meet the requirements of GB/T41244-2022, i.e. much better than just the morphology of eucalyptus staple, whereas the dispersion properties are much better than the screened bamboo pulp compared to the screened bamboo pulp fibers, achieving a balance of flushable properties and strength.

The foregoing description is only of embodiments of the present invention, and is not intended to limit the scope of the invention, and all equivalent structures or equivalent processes using the content of the present invention, or direct or indirect application in other related technical fields, are included in the scope of the present invention.

Claims (10)

1. The non-woven fabric capable of being scattered comprises natural fibers and viscose fibers which are entangled with each other, wherein the average length of the natural fibers is 1.5-3 mm, the length-to-width ratio is 80-160, the wall cavity ratio is greater than or equal to 1, the length of the viscose fibers is 4-10 mm, the viscose fibers account for 20% -25%, and the number ratio of the fibers with the length less than 1mm in the natural fibers is 4-10%.

2. The flushable nonwoven fabric of claim 1, wherein said natural fibers are bamboo pulp fibers.

3. The flushable nonwoven fabric of claim 2, wherein the viscose is a flat viscose and the length of the flat viscose is 4-7 mm.

4. The flushable nonwoven fabric of claim 2, wherein the natural fibers are first screened to form a first slurry having a length of 1.0mm or less and a second slurry having a length of 1.0mm or more before forming the flushable nonwoven fabric, and then the ratio of the first slurry to the second slurry is adjusted to form a mixed slurry, such that the fibers having a length of 1.0mm or less in the formed mixed slurry account for 4 to 10% of the natural fibers.

5. The flushable nonwoven fabric of claim 2, wherein the bamboo pulp fibers are a blend of at least two bamboo pulp fibers, and the aspect ratio of the blend bamboo pulp fibers is 80-100 and the wall cavity ratio is 1-3.

6. The flushable nonwoven fabric of claim 5, wherein the bamboo pulp fibers are a mixture of phyllostachys pubescens fibers and hybrid bamboo fibers, and the ratio of phyllostachys pubescens fibers to hybrid bamboo fibers is 50:50-70:30.

7. The flushable nonwoven fabric of claim 2, wherein the bamboo pulp fibers are 60% phyllostachys pubescens +40% hybrid bamboo, average fiber length: 1.72mm, an average aspect ratio of 92, and an average wall cavity ratio of 2.45, wherein the fiber length of less than 1mm is 7.6%.

8. The flushable nonwoven fabric of claim 2, wherein said bamboo pulp fibers are 100%

Arrowhead, average fiber length: 1.99mm, an average aspect ratio of 139, and an average wall cavity ratio of 1.9, wherein the fiber length of less than 1mm is 9.6%.

9. The flushable nonwoven fabric of claim 2, wherein said bamboo pulp fibers are 100%

Phyllostachys pubescens, average fiber length: 1.8mm, an average aspect ratio of 85, and an average wall cavity ratio of 2.1, wherein the fiber length of less than 1mm is 6.5%.

10. The flushable nonwoven fabric of any one of claims 1-9, having a water dispersibility of 90% or greater.