A kind of non-woven fabric for packaging and its preparation process

Abstract

The present invention belongs to the technical field of non-woven fabric packaging, and in particular, relates to a non-woven fabric for packaging and a preparation process thereof. Among them, a preparation process of a non-woven fabric for packaging includes fiber combing and fiber web shaping, and the non-woven fabric for packaging is obtained after the fiber web is shaped. The fiber used in the fiber combing step is a PE / PP core-skin composite fiber. By setting the melting point of the skin layer of the PE / PP core-skin composite fiber, the mass ratio of the skin layer to the core layer, the center distance between adjacent rolling points of the non-woven fabric for packaging and the hot pressing temperature, and compounding an epoxy resin coating containing wollastonite on the PE / PP core-skin composite fiber, the obtained non-woven fabric for packaging is safe and hygienic and has good air permeability, mechanical properties and boiling resistance.

Description

Technical Field

[0001] The invention belongs to the technical field of non-woven fabric packaging, and in particular relates to a non-woven fabric for packaging and a preparation process thereof. Background Art

[0002] Non-woven fabric is a kind of non-woven fabric, which is directly made of polymer slices, short fibers or filaments, and then formed into a non-woven fabric by airflow or mechanical web formation, and then reinforced by hydroentanglement, needle punching, or hot rolling, and finally finished. In daily life, non-woven fabrics are widely used as packaging materials, including desiccant packaging materials, deoxidizer packaging materials, tea bag and coffee bag packaging materials, seasoning bag packaging materials, packaging support layer materials and cooking packaging materials. Non-woven packaging materials are not only required to have certain tear resistance, but also require safety, non-toxicity, hygiene and convenience to form a protective layer around the product to isolate it.

[0003] Traditional steaming packaging materials include plastic film steaming materials and gauze steaming materials. Plastic film steaming materials require a hole-opening step during the production process, which is cumbersome. Gauze steaming materials cannot solve the problem of hair falling off the sealing part of the gauze material, and the gauze material is prone to aging under high temperature conditions, resulting in a decrease in the mechanical properties of the packaging material and the packaging material is extremely easy to break. At present, ordinary non-woven packaging materials have poor air permeability or weak bonding between fibers of non-woven packaging materials. Non-woven packaging materials are prone to stratification or even rupture under long-term steaming. Summary of the invention

[0004] In order to improve the problem that existing retort packaging materials are difficult to simultaneously have the characteristics of easy processing, resistance to retort, good air permeability, safety and hygiene, the present application provides a non-woven fabric for packaging and a preparation process thereof.

[0005] In a first aspect, the present application provides a process for preparing a nonwoven fabric for packaging, which adopts the following technical solution:

[0006] A preparation process of a non-woven fabric for packaging includes fiber combing and fiber web shaping, and the non-woven fabric for packaging is obtained after the fiber web is shaped; the fiber used in the fiber combing step is a PE / PP core-skin composite fiber, and the fiber used in the fiber combing step is a PE / PP core-skin composite fiber, and the skin layer is a PE material with a melting point of 110-130°C;

[0007] The center distance between adjacent rolling points of the non-woven fabric for packaging is 1.5-2.5 mm; the hot pressing temperature for shaping the fiber web is 125-135°C.

[0008] By adopting the above technical scheme, the PE / PP sheath-core composite fibers are combed to form a flat fiber web, and the skin fibers are melted and bonded to each other at the hot rolling points during the fiber web shaping process to prepare a non-woven fabric for packaging. The fibers outside the hot rolling points are still in a fluffy state, and the fibers between the points maintain air permeability, so that the prepared non-woven fabric for packaging has good mechanical properties, cooking resistance and air permeability.

[0009] By setting the skin layer of the PE / PP core-skin composite fiber to PE with a melting point of 125-135°C, and utilizing the thermoplastic properties of the skin of the core-skin structure fiber, the PE material is adhered during the fiber web shaping. With the appropriate hot pressing temperature and the appropriate length of adjacent rolling points, the skin layer PE is adhered without viscous flow, and the gaps between the fibers are not excessively blocked, so that the packaging non-woven fabric has good mechanical properties while maintaining excellent air permeability. At the same time, the melting point of the skin layer of the packaging non-woven fabric is 125-135°C, which is higher than the cooking temperature under normal atmospheric pressure, and can withstand long-term cooking without deformation.

[0010] The non-woven fabric for packaging is made of food-grade PE / PP core-skin composite fiber, and the center distance between adjacent tying points of the non-woven fabric in the fiber web shaping is 1.5-2.5mm, so that the edges of the prepared non-woven fabric for packaging are neat, and heat sealing and ultrasonic sealing can be used. The sealing is smooth, without scars or debris. The prepared non-woven fabric for packaging is safe and hygienic, and meets the safety and sanitation requirements of food packaging.

[0011] Preferably, the mass ratio of the skin layer to the core layer is (0.2-0.4):1.

[0012] By adopting the above technical solution, the mass ratio of the skin layer to the core layer, the melting point of the skin layer and the hot pressing temperature are controlled to control the amount of skin layer melting after the fiber web is formed. If the skin layer melting point is too low or the skin layer content is too high, the skin layer structure after hot melting may be deformed too much and block the gaps between the fibers, resulting in poor air permeability; if the skin layer melting point is too high or the skin layer content is too low, the adhesion between the PE / PP skin-core composite fibers may be insufficient, resulting in the non-woven fabric for packaging being unable to withstand long-term steaming and causing the non-woven fabric packaging material to be delaminated or even ruptured.

[0013] Preferably, in the fiber web formed after the fiber combing, 25%-45% of the PE / PP core-skin composite fibers are arranged in the transverse direction of the non-woven fabric for packaging, and 55%-75% of the PE / PP core-skin composite fibers are arranged randomly.

[0014] By adopting the above technical solution, PE / PP core-skin composite fibers are arranged transversely to enhance the transverse strength and reduce the damage and rupture of the non-woven fabric caused by the transverse impact of the expansion of the contents in the package on the non-woven fabric during the cooking process.

[0015] Preferably, the thickness of the prepared nonwoven fabric for packaging is 0.07-0.11 mm.

[0016] By adopting the above technical scheme, if the thickness of the non-woven fabric for packaging is too thin, the mechanical properties of the non-woven fabric for packaging are insufficient and the non-woven fabric for packaging is easy to break; if the thickness of the non-woven fabric for packaging is too thick, the air permeability of the non-woven fabric for packaging is easy to deteriorate. By selecting a suitable thickness of the non-woven fabric for packaging, the prepared non-woven fabric for packaging has good mechanical properties and good air permeability.

[0017] Preferably, the PE / PP core-skin composite fiber is impregnated with an impregnation solution A before the fiber combing step, wherein the impregnation solution A comprises 24-36 kg of epoxy resin, 2-4 kg of polyvinyl alcohol, 10-15 kg of polyglycerol fatty acid ester, 6-8 kg of wollastonite, 5-8 kg of ethanol and 40-60 kg of water in parts by weight;

[0018] The PE / PP core-skin composite fiber is treated in an impregnation liquid A under 5-10KHz ultrasonic vibration for 2-4 hours, and the temperature of the impregnation liquid A is 50-60° C. After the PE / PP core-skin composite fiber is impregnated with the impregnation liquid A, it is drained and dried at 30-50° C. for 6-10 hours;

[0019] The nonwoven fabric for packaging obtained after the fiber web is shaped is treated in an impregnation liquid B at a temperature of 40-60° C. under the action of 5-10KHz ultrasound for 2-4 hours, wherein the impregnation liquid B comprises 30-40 parts by weight of a dibasic acid, 1-2 parts of a chitosan quaternary ammonium salt, 5-8 parts of ethanol and 40-60 parts of water;

[0020] The non-woven fabric for packaging impregnated with the impregnation liquid B is reacted at 100-115° C. for 5-10 hours to obtain the non-woven fabric for packaging with an epoxy resin coating.

[0021] By adopting the above technical scheme, the PE / PP core-skin composite fiber is treated with the impregnation liquid A, so that the epoxy resin, polyvinyl alcohol, polyglycerol fatty acid ester and wollastonite in the impregnation liquid A adhere to the PE / PP core-skin composite fiber, wherein the polyvinyl alcohol and polyglycerol fatty acid ester promote the adhesion of wollastonite and enhance the adhesion of epoxy resin to the PE / PP core-skin composite fiber, and the 5-10KHz ultrasonic vibration is conducive to the adhesion of more wollastonite and epoxy resin to the PE / PP core-skin composite fiber.

[0022] The packaging non-woven fabric obtained after the fiber web is finalized is treated with impregnation liquid B, so that the dibasic acid and oleic acid are attached to the PE / PP core-skin composite fiber, and then the epoxy resin and the dibasic acid form a coating on the PE / PP core-skin composite fiber at 100-120°C, and a number of protrusions are formed on the surface of the PE / PP core-skin composite fiber in the wollastonite-wrapped adhesion coating, and the protrusions reduce the contact between the PE / PP core-skin composite fibers and increase the air permeability between the PE / PP core-skin composite fibers.

[0023] The epoxy resin coating formed at the bonding points of the PE / PP sheath-core composite fibers forms a protective layer at the bonding points of the PE / PP sheath-core composite fibers, which protects the bonding points of the PE / PP sheath-core composite fibers from direct impact of hot water or hot steam during the cooking process, thereby enhancing the mechanical strength and cooking resistance of the non-woven fabric for packaging.

[0024] Preferably, the epoxy resin is one of E44 and E50, and the dibasic acid is one of succinic acid, adipic acid or azelaic acid.

[0025] Preferably, the epoxy resin is E44, and the dibasic acid is adipic acid.

[0026] By adopting the above technical scheme, epoxy resin is preferred. The epoxy resin before curing maintains a certain viscosity, which is conducive to the adhesion of the epoxy resin to the PE / PP sheath-core composite fiber; the epoxy resin after curing maintains a certain softness, so that the prepared packaging non-woven fabric has a certain softness while maintaining excellent mechanical properties.

[0027] A dibasic acid with a small molecular weight is preferred. After being fully impregnated, the dibasic acid with a small molecular weight adheres to the PE / PP core-skin composite fiber and has better contact with the epoxy resin, thereby reacting.

[0028] Preferably, the impregnation solution B also includes 3-5 parts of dimethyl silicone oil and 6-8 parts of oleamide.

[0029] By adopting the above technical solution, dimethyl silicone oil and oleic acid amide are added to the impregnation liquid B, so that the prepared epoxy resin coating has hydrophobic properties and low surface tension, and the water permeability and air permeability of the non-woven fabric for packaging are increased.

[0030] Preferably, the impregnation solution B also includes 1-3 parts of pectin.

[0031] By adopting the above technical scheme, pectin is added to the impregnation liquid B to enhance the viscosity of the impregnation liquid B, thereby enhancing the adhesion performance of the dibasic acid on the PE / PP sheath-core composite fiber, allowing more dibasic acid to react with the epoxy resin, increasing the thickness of the prepared epoxy resin coating, and allowing more wollastonite to be coated in the epoxy resin coating, thereby enhancing the boiling resistance, mechanical properties and air permeability of the epoxy resin coating.

[0032] Preferably, the non-woven fabric for packaging obtained after the fiber web is shaped is impregnated with the impregnation liquid B and then placed at 30-50° C. for 8-15 minutes;

[0033] The non-woven fabric for packaging with epoxy resin coating is treated with an aqueous solution at a temperature of 70-80° C. under the action of 15-25 KHz ultrasonic waves for 10-20 minutes.

[0034] By adopting the above technical scheme, the non-woven fabric for packaging obtained after the fiber web is formed is impregnated with the impregnation liquid B and placed at 30-50°C for 8-15 minutes. The excess impregnation liquid B drips from the non-woven fabric. The low surface tension of the impregnation liquid B makes the impregnation liquid B on the non-woven fabric for packaging wrapped on the PE / PP core-skin composite fiber, and the PE / PP core-skin composite fibers do not adhere to each other, so that the dibasic acid reacts with the epoxy resin to form a coating wrapped on the PE / PP core-skin composite fiber, so that the prepared non-woven fabric for packaging has excellent air permeability and boiling resistance.

[0035] The non-woven fabric for packaging with epoxy resin coating is treated with an aqueous solution under ultrasonic vibration to remove the unreacted hydrophilic raw materials in the epoxy resin coating, thereby improving the hydrophobicity of the surface of the non-woven fabric for packaging with epoxy resin coating, thereby improving the water permeability and air permeability of the non-woven fabric for packaging with epoxy resin coating. In addition, wollastonite that is not well wrapped by the epoxy resin coating is removed through water treatment.

[0036] In a second aspect, the present application provides a nonwoven fabric for packaging.

[0037] A non-woven fabric for packaging is prepared by adopting the preparation process of the non-woven fabric for packaging in the present application.

[0038] By adopting the above technical scheme, the preparation process of the non-woven fabric for packaging is simple, and the obtained non-woven fabric packaging material for packaging is resistant to boiling, has good air permeability, and is safe and hygienic.

[0039] In summary, this application has the following beneficial effects:

[0040] 1. A preparation process of a non-woven fabric for packaging includes fiber combing and fiber web shaping. After the fiber web is shaped, the non-woven fabric for packaging is obtained. The fiber used in the fiber combing step is a PE / PP core-skin composite fiber. By setting the melting point of the skin layer of the PE / PP core-skin composite fiber, the mass ratio of the skin layer to the core layer, the center distance between adjacent rolling points of the non-woven fabric for packaging and the hot pressing temperature, the obtained non-woven fabric for packaging is safe and hygienic and has excellent air permeability, mechanical properties and cooking resistance.

[0041] 2. The PE / PP core-skin composite fiber is treated with impregnation liquid A, and the non-woven fabric for packaging obtained after the fiber web is finalized is treated with impregnation liquid B. The impregnation liquid A reacts with the impregnation liquid B to form an epoxy resin coating wrapped with wollastonite. The wollastonite forms small protrusions on the surface of the PE / PP core-skin composite fiber, which increases the air permeability between the PE / PP core-skin composite fibers. The epoxy resin coating forms a protective layer at the bonding point of the PE / PP core-skin composite fiber, which enhances the mechanical strength and cooking resistance of the non-woven fabric for packaging.

[0042] 3. The impregnation liquid B also includes dimethyl silicone oil, oleic acid amide and pectin. The non-woven fabric for packaging obtained after the fiber web is shaped is impregnated with the impregnation liquid B and then placed to remove excess impregnation liquid B. The low surface tension of the impregnation liquid B makes the impregnation liquid B on the non-woven fabric for packaging wrap around the PE / PP core-skin composite fiber. After the epoxy resin reacts with the dibasic acid, a protective layer is formed on the PE / PP core-skin composite fiber, thereby enhancing the mechanical properties, cooking resistance and air permeability of the non-woven fabric for packaging. DETAILED DESCRIPTION

[0043] Raw materials: PE / PP core-skin composite fiber (linear density about 2.0 dtex), wollastonite (particle size: 6.5μm-10μm), polyvinyl alcohol (CAS: 14-55-63, molecular weight: 124,000-130,000), epoxy resin (model: E44, E50, E51; food grade), (1,4)-2-acetamide-2-deoxy-β-D-polyglucose (CAS: 70694-72-3), 2-hydroxypropyltrimethylammonium chloride chitosan Sugar (CAS: 9012-76-4), dimethyl silicone oil (brand: YX-WL-80; hydroxyl value: 14-25mgKOH / g), oleamide (CAS: 301-02-0), succinic acid (CAS: 110-15-6), adipic acid (CAS: 124-04-9), azelaic acid (CAS: 123-99-9), pectin (CAS: 9000-69-5), citric acid (CAS: 77-92-9).

[0044] Example

[0045] Example 1

[0046] A preparation process of a nonwoven fabric for packaging, comprising the following preparation steps:

[0047] Impregnation liquid A treatment - fiber combing - fiber web shaping - impregnation liquid B treatment - epoxy resin film formation;

[0048] Impregnation liquid A treatment: The PE / PP core-skin composite fiber is treated with impregnation liquid A before the fiber combing step. The impregnation liquid A includes 24 kg of epoxy resin E44, 4 kg of polyvinyl alcohol, 15 kg of polyglycerol fatty acid ester, 6 kg of wollastonite, 5 kg of ethanol and 40 kg of water;

[0049] The PE / PP core-skin composite fiber was treated in the impregnation liquid A under 5KHz ultrasonic vibration for 4 hours, and the temperature of the impregnation liquid A was 50°C; after the PE / PP core-skin composite fiber was impregnated with the impregnation liquid A, it was drained to remove the surface water kg and then dried at 30°C for 6 hours;

[0050] The skin layer of the PE / PP skin-core composite fiber used is a PE material with a melting point of 120°C, the core layer is a PP material with a melting point of 165°C, and the mass ratio of the skin layer to the core layer is 0.2:1.

[0051] Fiber combing: The PE / PP core-skin composite fiber is discharged in the disc mixer and evenly picked up by the turntable and put into the mixing bin. The air volume parameters of the high-cotton box are adjusted to form a fiber layer of the PE / PP core-skin composite fiber. The fiber layer is pre-combed and combed, and the speed ratio of the needle clothing is adjusted to comb the disordered fibers individually to form a flat fiber web.

[0052] Fiber web shaping: The fiber web is heated and melted in a hot rolling mill, wherein 25% of the PE / PP core-skin composite fibers in the fiber web are arranged transversely, and 75% of the PE / PP core-skin composite fibers are arranged randomly; the center distance between adjacent rolling points of the non-woven fabric for packaging is 1.5 mm, the rolling mill temperature is 125°C, the pressure of the hot rolling roll is 20 MPa, and the fibers are fused together at the hot rolling point to obtain a non-woven fabric for packaging with a thickness of 0.07 mm.

[0053] Treatment with impregnation liquid B: The nonwoven fabric for packaging obtained after the fiber web is shaped is treated in an impregnation liquid B at a temperature of 60° C. under the action of 5KHz ultrasound for 2 hours. The impregnation liquid B includes 30kg of succinic acid, 1kg of chitosan quaternary ammonium salt, 5kg of ethanol and 40kg of water.

[0054] Epoxy resin film formation: The packaging nonwoven fabric impregnated with the impregnation liquid B was reacted at 100° C. for 10 hours to obtain an epoxy resin coating.

[0055] Example 2-3

[0056] A preparation process of a non-woven fabric for packaging, which is different from Example 1 in that the melting point, cutting length and weight ratio of the skin layer of the PE / PP core-skin composite fiber are set differently; the raw material type and ratio, temperature, treatment time, ultrasonic action frequency and time and drying conditions after impregnation of the impregnation liquid A are set differently; the length of adjacent pricking points in the fiber web shaping, the hot pressing temperature and the thickness of the non-woven fabric for packaging obtained are set differently; the raw material type and ratio of the impregnation liquid B in the impregnation liquid B treatment, the temperature and impregnation time of the impregnation liquid B, the ultrasonic action frequency and time are set differently; the film forming temperature and film forming time in the epoxy resin film forming are set differently, as shown in Table 1-2:

[0057] Table 1 Melting point, cut length and weight ratio of the skin layer of PE / PP skin-core composite fibers in Examples 1-3; Parameter list for setting the length of adjacent pricking points, hot pressing temperature, fiber arrangement and thickness of the obtained nonwoven fabric for packaging in fiber web shaping

[0058]

[0059] Table 2 Parameter list of raw material types, proportions and processing conditions of the impregnation liquid A in Examples 1-3; raw material types, proportions and processing conditions of the impregnation liquid B; film forming temperature conditions of the epoxy resin

[0060]

[0061]

[0062]

[0063] Example 4

[0064] A preparation process of a non-woven fabric for packaging, which differs from Example 1 in that: the hot pressing temperature for shaping the fiber web is 135° C.; and the mass ratio of the skin layer to the core layer is 0.5:1.

[0065] Example 5

[0066] A preparation process of a non-woven fabric for packaging, which differs from Example 1 in that the PE / PP core-skin composite fibers are randomly arranged in the fiber web formed after the fibers are combed.

[0067] Example 6

[0068] A preparation process of a non-woven fabric for packaging, which differs from Example 1 in that: the thickness of the prepared non-woven fabric for packaging is 0.13 mm; and the mass ratio of the skin layer to the core layer is 0.5:1.

[0069] Example 7

[0070] A preparation process of a non-woven fabric for packaging, which differs from Example 1 in that the epoxy resin used in the impregnation liquid A is of type E51, and the dibasic acid used in the impregnation liquid B is citric acid.

[0071] Embodiment 8-10

[0072] A preparation process of a non-woven fabric for packaging, which differs from Example 1 in that: the impregnation liquid B also includes dimethyl silicone oil, oleic acid amide and pectin, the specific weights are shown in Table 3, and the non-woven fabric for packaging obtained after the fiber web is shaped is impregnated with the impregnation liquid B and then placed, the placement conditions are shown in Table 3; and the non-woven fabric for packaging with an epoxy resin coating is treated with an aqueous solution, the treatment conditions are shown in Table 3.

[0073] The difference between Examples 8-10 is that the weight of the raw materials in the impregnation liquid B is set differently, the placement conditions of the packaging non-woven fabric after being impregnated with the impregnation liquid B are set differently, and the treatment conditions of the aqueous solution are different, as shown in Table 3.

[0074] Table 3 Parameter list of weight settings of raw materials in the impregnation solution B, placement conditions of the nonwoven fabric for packaging after impregnation with the impregnation solution B, and aqueous solution treatment conditions in Examples 8-10

[0075]

[0076]

[0077] Embodiment 11

[0078] A process for preparing a non-woven fabric for packaging, which differs from Example 8 in that: after the non-woven fabric for packaging is prepared after the fiber web is shaped, no standing time is set after it is impregnated with the impregnation liquid B, and no aqueous solution treatment is used.

[0079] Example 12

[0080] A process for preparing a non-woven fabric for packaging, which differs from Example 8 in that: pectin is not provided in the impregnation liquid B, and the non-woven fabric for packaging obtained after the fiber web is shaped is not placed for a period of time after being impregnated with the impregnation liquid B, and is not treated with an aqueous solution.

[0081] Example 13

[0082] A process for preparing a non-woven fabric for packaging, which differs from Example 8 in that: the impregnation liquid A is not used to impregnate the PE / PP core-skin composite fiber before the fiber combing step; and the non-woven fabric for packaging obtained after the fiber web is formed is not impregnated with the impregnation liquid B.

[0083] Comparative Example

[0084] Comparative Example 1

[0085] A preparation process of a non-woven fabric for packaging, using PE fibers, after the fibers are combed into a fiber web, the center distance between adjacent nip points of the non-woven fabric for packaging is 2.5 mm; the hot pressing temperature is 125°C, and a non-woven fabric for packaging with a thickness of 0.07 mm is obtained.

[0086] Comparative Example 2

[0087] A preparation process for nonwoven fabric for packaging, using PP fibers, after the fibers are combed into a fiber web, the center distance between adjacent rolling points of the prepared nonwoven fabric for packaging is 0.5 mm; the hot pressing temperature is 175°C, and the nonwoven fabric for packaging with a thickness of 0.07 mm is prepared.

[0088] Comparative Example 3

[0089] A preparation process of a non-woven fabric for packaging, which differs from Example 1 in that: the center distance between adjacent rolling points of the prepared non-woven fabric for packaging is 3 mm; the hot pressing temperature for shaping the fiber web is 120°C; and the mass ratio of the skin layer to the core layer is 0.1:1.

[0090] Performance testing

[0091] Test 1: Mechanical strength test method: According to GB-T24218.3-2010 "Test methods for nonwoven fabrics of textiles", the mechanical strength of the experimental samples before and after high-temperature cooking was tested. The high-temperature cooking conditions were 121°C high-temperature steam for 40 minutes.

[0092] Test samples: The nonwoven fabrics for packaging prepared in Examples 1-13 were used as test samples, and the nonwoven fabrics for packaging prepared in Comparative Examples 1-3 were used as control samples.

[0093] Test results: The test results of the longitudinal tensile strength of the nonwoven fabrics for packaging prepared in Examples 1-13 and Comparative Examples 1-3 are shown in Table 4:

[0094] Test 2: Air permeability test method: Use an air permeability meter to measure the air permeability of two groups of non-woven fabrics, usually expressed as air permeability, that is, the amount of air passing through a unit area of ​​non-woven fabric per unit time under the condition of maintaining a certain pressure difference on both sides of the non-woven fabric, calculated according to the formula: BP (ml / cm2·s) = V / AF*T; where: V is the amount of air passing through the non-woven fabric in T seconds (mL); AF is the area of ​​the non-woven fabric (cm 2 The air permeability of nonwoven fabrics is characterized by measuring the air flow rate passing vertically through the sample per unit time under a specified pressure.

[0095] Test samples: The nonwoven fabrics for packaging prepared in Examples 1-13 were used as test samples, and the nonwoven fabrics for packaging prepared in Comparative Examples 1-3 were used as control samples.

[0096] Test results: The air permeability test results of the nonwoven fabrics for packaging prepared in Examples 1-13 and Comparative Examples 1-3 are shown in Table 4:

[0097] Table 4 Longitudinal tensile strength and air permeability of the nonwoven fabrics for packaging prepared in Examples 1-13 and Comparative Examples 1-3

[0098]

[0099] Combining Examples 1-13 and Comparative Examples 1-3 and Table 4, it can be seen that:

[0100] The longitudinal tensile strength (80-102 N / 5 cm) and longitudinal tensile strength (40-59 N / 5 cm) of the non-woven fabric for packaging prepared in Examples 1-13 before boiling are significantly better than the longitudinal tensile strength (48-75 N / 5 cm) and longitudinal tensile strength (24-35 N / 5 cm) of the non-woven fabric for packaging prepared in Comparative Examples 1-3 before boiling.

[0101] The longitudinal tensile strength (58-87N / 5cm) and longitudinal tensile strength (25-45N / 5cm) of the non-woven fabric for packaging prepared in Example 1-13 after boiling are better than the longitudinal tensile strength (36-50N / 5cm) and longitudinal tensile strength (19-23N / 5cm) of the non-woven fabric for packaging prepared in Comparative Example 1-3 after boiling.

[0102] The air permeability of the non-woven fabric for packaging prepared in Example 1-13 is 82-99 ml / cm2·s, which is better than the air permeability of the non-woven fabric for packaging prepared in Comparative Example 1-2, which is 70-78 ml / cm2·s.

[0103] It is shown that by setting the hot pressing temperature in the preparation process of the non-woven fabric for packaging, setting the center distance between adjacent pricking points of the non-woven fabric, and preferably setting the melting point of the skin layer of the PE / PP skin-core composite fiber and the weight ratio of the skin layer and the core layer, adding transversely arranged fibers, and by composite epoxy resin coating on the PE / PP skin-core composite fiber, the non-woven fabric for packaging has excellent mechanical properties. Although the air permeability of the non-woven fabric for packaging prepared in Comparative Example 3 is 89 ml / cm2·s, which is better than that in Example 1, the longitudinal tensile strength and transverse tensile strength of the non-woven fabric for packaging prepared in Comparative Example 3 are significantly lower than those in Example 1, and the comprehensive performance is poor.

[0104] It can be seen from Examples 1-3 and Examples 8-12 combined with Table 2 that:

[0105] In the impregnation liquid B, dimethyl silicone oil, oleic acid amide and pectin are used in combination with each other, and the non-woven fabric for packaging obtained after the fiber web is shaped is placed for a period of time after being impregnated with the impregnation liquid B, so that the prepared non-woven fabric for packaging has excellent longitudinal tensile strength and transverse tensile strength, boiling resistance and air permeability. It may be because the dimethyl silicone oil, oleic acid amide and pectin are used in combination with each other so that the impregnation liquid B has a low surface tension, and then the impregnation liquid B can be better wrapped on the PE / PP skin-core composite fiber and form a hydrophobic coating, so that the PE / PP skin-core composite fibers do not adhere to each other, so that the dibasic acid reacts with the epoxy resin to form a coating wrapped on the PE / PP skin-core composite fiber, and the wollastonite in the epoxy resin coating can better play the effect of reducing the contact between the PE / PP skin-core composite fibers and increasing the air permeability between the fibers, so that the prepared non-woven fabric for packaging has excellent longitudinal tensile strength and transverse tensile strength, boiling resistance and air permeability.

[0106] This specific embodiment is merely an explanation of the present application and is not a limitation of the present application. After reading this specification, those skilled in the art may make modifications to the present embodiment without any creative contribution as needed, but such modifications are protected by the patent law as long as they are within the scope of the claims of the present application.

Claims

1. A process for preparing a nonwoven fabric for packaging, characterized in that: Including fiber combing and fiber web shaping, after the fiber web shaping, the non-woven fabric for packaging is obtained; The fiber used in the fiber combing step is a PE / PP core-skin composite fiber, and the skin layer is a PE material with a melting point of 110-130°C; The center distance between adjacent nip points of the nonwoven fabric for packaging is 1.5-2.5 mm; the hot pressing temperature for shaping the fiber web is 125-135°C; The PE / PP core-skin composite fiber is impregnated with an impregnation liquid A before the fiber combing step, wherein the impregnation liquid A comprises 24-36 kg of epoxy resin, 2-4 kg of polyvinyl alcohol, 10-15 kg of polyglycerol fatty acid ester, 6-8 kg of wollastonite, 5-8 kg of ethanol and 40-60 kg of water by weight; the epoxy resin is E44 or E50, and the dibasic acid is one of succinic acid, adipic acid or azelaic acid; The PE / PP core-skin composite fiber is treated in an impregnation liquid A under 5-10KHz ultrasonic vibration for 2-4 hours, and the temperature of the impregnation liquid A is 50-60° C. After the PE / PP core-skin composite fiber is impregnated with the impregnation liquid A, it is drained and dried at 30-50° C. for 6-10 hours; The nonwoven fabric for packaging obtained after the fiber web is shaped is treated in an impregnation liquid B at a temperature of 40-60° C. under the action of 5-10KHz ultrasound for 2-4 hours, wherein the impregnation liquid B comprises 30-40 parts by weight of a dibasic acid, 1-2 parts of a chitosan quaternary ammonium salt, 5-8 parts of ethanol and 40-60 parts of water; The non-woven fabric for packaging impregnated with the impregnation liquid B is reacted at 100-115° C. for 5-10 hours to obtain the non-woven fabric for packaging with an epoxy resin coating.

2. The process for preparing the nonwoven fabric for packaging according to claim 1, characterized in that: The mass ratio of the skin layer to the core layer is (0.2-0.4):

1.

3. The process for preparing the nonwoven fabric for packaging according to claim 1, characterized in that: In the fiber web formed after the fiber is combed, 25%-45% of the PE / PP core-skin composite fibers are arranged along the transverse direction of the non-woven fabric for packaging, and 55%-75% of the PE / PP core-skin composite fibers are arranged randomly.

4. The process for preparing the nonwoven fabric for packaging according to claim 1, characterized in that: The thickness of the prepared nonwoven fabric for packaging is 0.07-0.11 mm.

5. The process for preparing the nonwoven fabric for packaging according to claim 1, characterized in that: The impregnation solution B also includes 3-5 parts of dimethyl silicone oil and 6-8 parts of oleamide.

6. The process for preparing the nonwoven fabric for packaging according to claim 5, characterized in that: The soaking liquid B also includes 1-3 parts of pectin.

7. The process for preparing the nonwoven fabric for packaging according to claim 6, characterized in that: The nonwoven fabric for packaging obtained after the fiber web is shaped is impregnated with the impregnation liquid B and then placed at 30-50° C. for 8-15 minutes; The non-woven fabric for packaging with epoxy resin coating is treated with an aqueous solution at a temperature of 70-80° C. under the action of 15-25 KHz ultrasonic waves for 10-20 minutes.

8. A nonwoven fabric for packaging, characterized in that: The nonwoven fabric is prepared by the preparation process of the nonwoven fabric for packaging as described in any one of claims 1 to 7.

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