A meltblown polylactic acid composition and a meltblown polylactic acid fiber web

Abstract

The present invention provides a meltblown polylactic acid composition and a meltblown polylactic acid fiber web. The meltblown polylactic acid composition is composed of 100 parts by weight of polylactic acid and 0.05 to 5 parts by weight of polysiloxane of formula (1). The meltblown polylactic acid composition can maintain the good strength of polylactic acid while having high fluidity.

Description

Technical Field

[0001] This invention belongs to the field of polymer chemical materials technology, specifically relating to a meltblown polylactic acid composition and a meltblown polylactic acid fiber web. Background Technology

[0002] Meltblown fiber webs are made by heating and melting meltblown resin, then drawing the molten filaments at high speed under the action of high-speed air to form ultrafine fiber webs. They are widely used in medical and health, gas-liquid filtration, and agriculture industries. Currently, the main meltblown resins are polypropylene (PP) and polyethylene terephthalate (PET). Polylactic acid (PLA) is a synthetic, biodegradable thermoplastic aliphatic polyester polymer material. Its main raw materials are derived from natural materials such as corn. It is environmentally friendly, has good plasticity, and is easy to process and mold. Therefore, some research has been conducted on using it to replace polypropylene in the preparation of meltblown fiber webs. As a meltblown resin material, high fluidity is usually required. For polylactic acid resin, high fluidity means a lower molecular weight, which can easily lead to low fiber strength. Therefore, it is necessary to develop polylactic acid meltblown resins with high fluidity without sacrificing the molecular weight (strength) of polylactic acid. Summary of the Invention

[0003] To address the technical problems described in the background section, the present invention provides a meltblown polylactic acid composition that maintains good strength while exhibiting high fluidity, and a meltblown polylactic acid fiber web prepared from the meltblown polylactic acid composition, the specific solutions of which are as follows:

[0004] A meltblown polylactic acid composition comprising: 100 parts by weight of polylactic acid, and 0.05 to 5 parts by weight of a polysiloxane of formula (1).

[0005]

[0006] In equation (1), R1 is a hydrogen atom or C 1-4 Alkyl group, R2 is C 1-4 The alkyl group, R3 and R4 are independent linking groups, R5 and R6 are independent hydrogen atoms, hydroxyl groups, amino groups, carboxyl groups or polylactic acid segments, and n is an integer from 10 to 10000.

[0007] Preferably, R1 and R2 are methyl groups, and the linking group has 1 to 3 carbon atoms. 1-4 It consists of alkylene groups and groups consisting of 0 to 3 ether oxygen atoms.

[0008] Preferably, R5 and R6 are each independently a hydrogen atom or a hydroxyl group.

[0009] Preferably, R5 is a hydrogen atom and R6 is a polylactic acid segment.

[0010] Preferably, the meltblown polylactic acid composition further includes 0.01 to 1 part by weight of cage-like polysilsesquioxane.

[0011] Preferably, the cage-like polysilsesquioxane is a dimethylsilyl cage-like polysilsesquioxane or a trimethylsilyl cage-like polysilsesquioxane.

[0012] Preferably, n is an integer from 40 to 60.

[0013] Preferably, the number-average molecular weight of the polylactic acid segments is 3000 to 5000.

[0014] Preferably, the melt index of the polylactic acid is 20-40 g / 10 min.

[0015] A meltblown polylactic acid (PLA) meltblown fiber mesh, wherein the PLA meltblown fiber mesh is prepared from any of the above-described PLA compositions by a meltblown process.

[0016] The present invention relates to a meltblown polylactic acid composition and a meltblown polylactic acid fiber web, wherein the meltblown polylactic acid composition comprises 100 parts by weight of polylactic acid and 0.05 to 5 parts by weight of polysiloxane of formula (1), and the meltblown polylactic acid composition can maintain the good strength of polylactic acid while having high fluidity. Detailed Implementation

[0017] A specific embodiment of the present invention provides a meltblown polylactic acid composition, the meltblown polylactic acid composition comprising: 100 parts by weight of polylactic acid, and 0.05 to 5 parts by weight of a polysiloxane with the structure of formula (1) below.

[0018]

[0019] In equation (1), R1 is a hydrogen atom or C 1-4 Alkyl group, R2 is C 1-4 The alkyl group, R3 and R4 are each independently a linking group, R5 and R6 are each independently a hydrogen atom, hydroxyl group, amino group, carboxyl group or polylactic acid segment, and n is an integer from 10 to 10000. The meltblown polylactic acid composition of the specific embodiments of the present invention can maintain good strength while having high fluidity by adding polysiloxane of formula (1).

[0020] The meltblown polylactic acid composition of the present invention, wherein C 1-4 The alkyl group can be, for example, methyl, ethyl, propyl, isopropyl, butyl, or isobutyl, and in some specific embodiments, R1 and R2 are both methyl.

[0021] In the meltblown polylactic acid composition of the present invention, R3 and R4 are each independently a linking group. In some specific embodiments, the linking group is a linking bond; in some specific embodiments, the linking group has 1 to 3 carbon atoms. 1-4 Alkylene groups and groups consisting of 0 to 3 ether oxygen atoms, specifically, for example, C 1-8 Alkyl groups, such as methylene, ethylene, propylene, isopropylene, butylene, isobutylene, or hexylene, etc., -CH2OCH2-, -CH2CH2OCH2CH2-, -CH2CH2CH2OCH2CH2CH2-, -CH2CH2OCH2CH2OCH2CH2-, or -CH2CH2OCH2CH2O-, etc.

[0022] In some specific embodiments of the meltblown polylactic acid composition of the present invention, R5 and R6 are independently hydrogen atoms or hydroxyl groups, that is, the polysiloxane with the structure of formula (1) is an alkyl-terminated polysiloxane, a monohydroxy-terminated polysiloxane, or a dihydroxy-terminated polysiloxane.

[0023] In some specific embodiments of the meltblown polylactic acid composition of the present invention, at least one of R5 and R6 is a polylactic acid segment. Such a meltblown polylactic acid composition has better flowability. In particular, R5 is a hydrogen atom and R6 is a polylactic acid segment, that is, the polysiloxane is a diblock copolymer of polysiloxane and polylactic acid, which has even better flowability.

[0024] In some specific embodiments of the meltblown polylactic acid composition of the present invention, n is an integer from 40 to 60, and further n is an integer from 45 to 55. Specifically, n can be, for example, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54 or 55.

[0025] In some specific embodiments of the meltblown polylactic acid composition of the present invention, the number average molecular weight of the polylactic acid segments is 3000 to 5000. Specifically, the number average molecular weight of the polylactic acid segments can be about 3000, 3200, 3500, 3800, 4000, 4200, 4500, 4800 or 5000. The polylactic acid segments with the specified number average molecular weight provide better flowability improvement to the meltblown polylactic acid composition.

[0026] In some specific embodiments of the meltblown polylactic acid composition of the present invention, based on 100 parts by weight of polylactic acid, the polysiloxane of formula (1) is 0.1 to 1 part by weight, specifically for example, 0.1 parts by weight, 0.2 parts by weight, 0.3 parts by weight, 0.4 parts by weight, 0.5 parts by weight, 0.6 parts by weight, 0.7 parts by weight, 0.8 parts by weight, 0.9 parts by weight, or 1 part by weight, etc.

[0027] In some specific embodiments, the meltblown polylactic acid composition of the present invention further includes 0.01 to 1 part by weight of a cage-like polysilsesquioxane. The cage-like polysilsesquioxane can be combined with a polysiloxane of formula (1), and in particular, when the polysiloxane is a diblock copolymer of polysiloxane and polylactic acid, the flowability of the meltblown polylactic acid composition can be further improved.

[0028] In some specific embodiments of the meltblown polylactic acid composition of the present invention, the cage-like polysilsesquioxane is a dimethylsilyl cage-like polysilsesquioxane or a trimethylsilyl cage-like polysilsesquioxane.

[0029] In some specific embodiments of the meltblown polylactic acid composition of the present invention, the cage-like polysilsesquioxane is 0.05 to 0.5 parts by weight, specifically, for example, 0.05 parts by weight, 0.06 parts by weight, 0.07 parts by weight, 0.08 parts by weight, 0.09 parts by weight, 0.1 parts by weight, 0.15 parts by weight, 0.2 parts by weight, 0.25 parts by weight, 0.25 parts by weight, 0.3 parts by weight, 0.35 parts by weight, 0.4 parts by weight, 0.45 parts by weight, or 0.5 parts by weight, etc.

[0030] In some specific embodiments of the meltblown polylactic acid composition of the present invention, the melt index of the polylactic acid is 20 to 40 g / 10 min, specifically, for example, 20 g / 10 min, 25 g / 10 min, 30 g / 10 min, 35 g / 10 min or 40 g / 10 min, etc., and the melt index is determined according to ASTM D1238 at 190°C and 2.16 kg.

[0031] In some specific embodiments, the meltblown polylactic acid composition of the present invention mainly consists of polylactic acid and a polysiloxane of formula (1), or polylactic acid, a polysiloxane of formula (1), and a cage-like polysilsesquioxane. It may also include conventional additives, such as antioxidants and UV stabilizers. In some specific embodiments, the meltblown polylactic acid composition may also include fillers such as calcium carbonate and talc. In some specific embodiments, the meltblown polylactic acid composition may also include impact modifiers such as PBAT, which can be added according to the actual application.

[0032] In some specific embodiments, the meltblown polylactic acid composition of the present invention can be prepared by uniformly mixing raw materials using commonly used mixing equipment, such as by twin-screw mixing and granulation.

[0033] The present invention also provides a polysiloxane containing polylactic acid segments, the polysiloxane having the structure shown in formula (1), wherein R1 is a hydrogen atom or C 1-4Alkyl group, R2 is C 1-4 The alkyl group, R3 and R4 are independent linking groups, R5 is a hydrogen atom or a polylactic acid segment, R6 is a polylactic acid segment, and n is an integer from 10 to 10000.

[0034] The polysiloxane containing polylactic acid segments of the present invention is further described above regarding R1, R2, R3, R4, n and the polylactic acid segments, etc.

[0035] The polysiloxane containing polylactic acid segments of the present invention can be prepared by ring-opening polymerization of lactide with monohydroxy-terminated or dihydroxy-terminated polysiloxane.

[0036] In some specific embodiments of the polylactic acid segment-containing polysiloxane of the present invention, as described above, the polylactic acid segment-containing polysiloxane can be used as an additive for meltblown polylactic acid to improve flowability while maintaining good strength of polylactic acid. In some specific embodiments, the polylactic acid segment-containing polysiloxane can also be used for other purposes.

[0037] The present invention also provides a meltblown polylactic acid (PLA) meltblown fiber mesh, which is prepared from the above-described PLA composition by a meltblown process.

[0038] The meltblown polylactic acid meltblown fiber mesh of the present invention can be applied to medical and health applications, such as meltblown fabric for masks, gas-liquid filtration, such as meltblown filter mesh, and agriculture, such as agricultural film and seed placement platforms.

[0039] The technical solution of the present invention will be further described below with reference to embodiments and comparative examples.

[0040] Example

[0041] The melt flow index in the following examples and comparative examples was determined according to ASTM D1238 at 190°C and 2.16 kg, and the tensile strength was determined according to ASTM D638.

[0042] Preparation of polysiloxanes containing polylactic acid segments

[0043] A monohydroxyl-terminated polydimethylsiloxane (Mn approximately 4500) was used to perform a ring-opening reaction on lactide at 170°C under the catalysis of stannous octoate. By controlling the molar ratio of monohydroxyl-terminated polydimethylsiloxane to lactide, polylactic acid segment number-average molecular weights of approximately 2000, 3000, 4500, 10000, and 15000 were prepared, respectively.

[0044] A polylactic acid-polydimethylsiloxane-polylactic acid triblock copolymer with a total number average molecular weight of approximately 4500 was prepared by reacting dihydroxyl-terminated polydimethylsiloxane (Mn approximately 4500) with lactide at 170°C under the catalysis of stannous octoate. By controlling the molar ratio of monohydroxyl-terminated polydimethylsiloxane to lactide, a polylactic acid-polydimethylsiloxane-polylactic acid triblock copolymer with a total number average molecular weight of approximately 4500 for the two polylactic acid segments was obtained.

[0045] Example 1

[0046] 3 kg of pre-dried Fengyuan FY202 polylactic acid was mixed with 15 g of monohydroxy-terminated polydimethylsiloxane (Mn approximately 4500) and 6 g of antioxidant 1010, and then granulated by twin-screw extruder at 190 °C to prepare a meltblown polylactic acid composition. The melt index and tensile strength results are listed in Table 1 below.

[0047] Example 2

[0048] 3 kg of pre-dried Fengyuan FY202 polylactic acid was mixed with 15 g of polysiloxane containing polylactic acid segments (polylactic acid segment Mn is about 2000) prepared by monohydroxy-terminated polydimethylsiloxane and 6 g of antioxidant 1010. The mixture was then granulated by twin-screw extruder at 190°C to prepare the melt-blown polylactic acid composition. The melt index and tensile strength results are listed in Table 1 below.

[0049] Example 3

[0050] 3 kg of pre-dried Fengyuan FY202 polylactic acid was mixed with 15 g of polysiloxane containing polylactic acid segments (polylactic acid segment Mn is about 3000) prepared by monohydroxy-terminated polydimethylsiloxane and 6 g of antioxidant 1010. The mixture was then granulated by twin-screw extruder at 190°C to prepare a meltblown polylactic acid composition. The melt index and tensile strength results are listed in Table 1 below.

[0051] Example 4

[0052] 3 kg of pre-dried Fengyuan FY202 polylactic acid was mixed with 15 g of polysiloxane containing polylactic acid segments (polylactic acid segment Mn is about 4500) prepared by monohydroxy-terminated polydimethylsiloxane and 6 g of antioxidant 1010. The mixture was then granulated by twin screw extruder at 190°C to prepare a meltblown polylactic acid composition. The melt index and tensile strength results are listed in Table 1 below.

[0053] Example 5

[0054] 3 kg of pre-dried Fengyuan FY202 polylactic acid was mixed with 15 g of polysiloxane containing polylactic acid segments (polylactic acid segment Mn is about 10000) prepared by monohydroxy-terminated polydimethylsiloxane and 6 g of antioxidant 1010. The mixture was then granulated by twin screw extruder at 190°C to prepare a meltblown polylactic acid composition. The melt index and tensile strength results are listed in Table 1 below.

[0055] Example 6

[0056] 3 kg of pre-dried Fengyuan FY202 polylactic acid was mixed with 15 g of polysiloxane containing polylactic acid segments (polylactic acid segment Mn is about 15000) prepared by monohydroxy-terminated polydimethylsiloxane and 6 g of antioxidant 1010. The mixture was then granulated by twin screw extruder at 190°C to prepare the meltblown polylactic acid composition. The melt index and tensile strength results are listed in Table 1 below.

[0057] Example 7

[0058] 3 kg of pre-dried Fengyuan FY202 polylactic acid was mixed with 15 g of polysiloxane containing polylactic acid segments (polylactic acid segment Mn is about 4500) prepared by dihydroxy-terminated polydimethylsiloxane and 6 g of antioxidant 1010. The mixture was then granulated by twin-screw extruder at 190°C to prepare a meltblown polylactic acid composition. The melt index and tensile strength results are listed in Table 1 below.

[0059] Example 8

[0060] 3 kg of pre-dried Fengyuan FY202 polylactic acid was mixed with 3 g of polysiloxane containing polylactic acid segments (polylactic acid segment Mn is about 4500) prepared by monohydroxy-terminated polydimethylsiloxane and 6 g of antioxidant 1010. The mixture was then granulated by twin-screw extruder at 190°C to prepare a meltblown polylactic acid composition. The melt index and tensile strength results are listed in Table 1 below.

[0061] Example 9

[0062] 3 kg of pre-dried Fengyuan FY202 polylactic acid was mixed with 45 g of polysiloxane containing polylactic acid segments (polylactic acid segment Mn is about 4500) prepared by monohydroxy-terminated polydimethylsiloxane and 6 g of antioxidant 1010. The mixture was then granulated by twin-screw extruder at 190°C to prepare a meltblown polylactic acid composition. The melt index and tensile strength results are listed in Table 1 below.

[0063] Example 10

[0064] 3 kg of pre-dried Fengyuan FY202 polylactic acid was mixed with 15 g of polysiloxane containing polylactic acid segments (polylactic acid segment Mn is about 4500) prepared from monohydroxy-terminated polydimethylsiloxane, 3 g of dimethylsilyl cage polysilsesquioxane, and 6 g of antioxidant 1010. The mixture was then granulated by twin-screw extruder at 190 °C to prepare a meltblown polylactic acid composition. The melt index and tensile strength results are listed in Table 1 below.

[0065] Comparative Example 1

[0066] 3 kg of pre-dried Fengyuan FY202 polylactic acid was mixed with 6 g of antioxidant 1010 and then granulated by twin-screw extruder at 190°C to prepare a meltblown polylactic acid composition. The melt index and tensile strength results are listed in Table 1 below.

[0067] Table 1 Test results of Examples 1-10 and Comparative Example 1

[0068] Melt index (g / 10min) Tensile strength (MPa) Example 1 65 47 Example 2 71 51 Example 3 75 48 Example 4 86 51 Example 5 73 50 Example 6 59 49 Example 7 67 48 Example 8 63 50 Example 9 85 45 Example 10 95 50 Comparative Example 1 30 50

[0069] As shown in Table 1 above, in Examples 1-10, the addition of polydimethylsiloxane, especially polylactic acid and polydimethylsiloxane diblock copolymer, can greatly improve the fluidity of meltblown polylactic acid. Furthermore, by controlling the amount added, the tensile strength of meltblown polylactic acid can be maintained. In particular, as in Example 10, when the meltblown polylactic acid composition contains dimethylsilyl cage polysilsesquioxane, the fluidity of high meltblown polylactic acid can be further improved. For polylactic acid and polydimethylsiloxane diblock copolymer, the effect is best when the molecular weight of the polylactic acid segment is around 4500.

[0070] While the present invention has been disclosed above, it is not limited thereto. Any person skilled in the art can make various modifications and alterations without departing from the spirit and scope of the invention; therefore, the scope of protection of the present invention should be determined by the scope defined in the claims.

Claims

1. A melt-blown polylactic acid composition, characterized in that, The melt-blown polylactic acid composition comprises: 100 parts by weight of polylactic acid, 0.05 to 5 parts by weight of polysiloxane having a structure of formula (1), In formula (1), R1 is a hydrogen atom or a C 1-4 alkyl group, R2 is a C 1-4 alkyl group, R3 and R4 are each independently a linking group, R5 is a hydrogen atom, R6 is a polylactic acid segment, n is an integer of 40 to 60, and the polylactic acid segment has a number average molecular weight of 3000 to 5000.

2. The melt-blown polylactic acid composition according to claim 1, characterized in that, R1and R2are methyl, the linking group is a group consisting of 1 to 3 C 1-4 alkylene groups and 0 to 3 ether oxygen atoms.

3. The melt-blown polylactic acid composition according to claim 1, wherein, The melt-blown polylactic acid composition further comprises: 0.01 to 1 parts by weight of cage polysilsesquioxane.

4. The melt-blown polylactic acid composition according to claim 3, characterized in that, The cage polysilsesquioxane is dimethylsilyl cage polysilsesquioxane or trimethylsilyl cage polysilsesquioxane.

5. The melt-blown polylactic acid composition according to claim 1, wherein, The polylactic acid has a melt index of 20 to 40 g / 10 min.

6. A meltblown polylactic acid meltblown fiber web characterized in that, The melt-blown polylactic acid melt-blown fiber web is prepared by a melt-blown process using the melt-blown polylactic acid composition according to any one of claims 1 to 5.

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