Polylactic acid fiber filter rods processed by the group and their manufacturing method

Abstract

The present invention provides a polylactic acid fiber filter rod processed by group processing and its manufacturing method, which relates to the technical field of cigarette manufacturing. The polylactic acid fiber filter rod includes an inner core and an outer skin, the inner core and the outer skin are each composed of a plurality of polylactic acid fiber tows, the polylactic acid fiber tows in the inner core are made of a first component raw material, the polylactic acid fiber tows in the outer skin are made of a second component raw material, the content of L-lactic acid monomer in the first component raw material is higher than that in the second component raw material, a dispersant is added to the first component raw material, and glycerol triacetate is added to the second component raw material. The present invention is easy to install, and by strictly controlling the properties of the polylactic acid raw materials, all the outer layer skins have a uniform crystallinity, and all the inner layer cores also have a uniform crystallinity. When the tow crystallizes, the nodes are evenly distributed, and the inside and outside of the produced polylactic acid fiber filter rod have gradually changing crystallinity, so the processing process is more stable and the adsorption performance of the filter rod is ensured.

Description

[Technical field]

[0001] The present invention relates to the field of tobacco manufacturing technology, in particular, the present invention relates to a group processed polylactic acid fiber filter rod and a method for manufacturing the same. [Background technology]

[0002] Polylactic acid (PLA) is produced by fermenting starch from renewable plant resources to produce lactic acid, and then chemically synthesizing it into a polymer material. It has excellent recyclability and biodegradability, and has the following characteristics: 1. It is made from renewable plant resources (such as corn, wheat, sugar beet, rice, potato, taro, etc.) and organic waste (such as corn cobs or other crop roots, stems, leaves, and husks) as raw materials, which is free from dependence on wood and petroleum resources and meets the requirements of sustainable development. 2. It is completely biodegradable, and can be naturally decomposed into water and carbon dioxide after a certain period of time in the natural environment without causing environmental pollution, and the carbon dioxide produced is reused by the photosynthesis of plants, becoming an eternal closed carbon circulation system, and is a real "green material". 3. Compared with the three synthetic fibers of polyester, nylon, and acrylic, the energy consumption for producing polylactic acid fiber is relatively low, and it is a polymer material with relatively low burden on resources and the environment. 4. It has good processing performance, and the tow can be produced using the melt spinning method of general thermoplastic resins.

[0003] At present, polylactic acid fiber is being developed for fields such as tobacco tow, but the performance requirements of polylactic acid fiber for tobacco tow and conventional polylactic acid tow for clothing are significantly different. For example, polylactic acid fiber for clothing must meet the requirements of fiber spinning, weaving and fabric printing and dyeing, washing and ironing, must have a very high crystallinity, orientation and mechanical strength, can withstand temperatures of 80-100°C, must not dissolve and swell in detergent aqueous solutions and dry cleaning solvents, must have a certain degree of hygroscopicity, and at the same time, the less other gas substances in the surrounding environment the better. However, as a tobacco tow, it must meet the following requirements: (1) The wound filter rod is non-toxic, odorless and safe; (2) The stability of the tow is good, and it can meet the requirements of the filter rod forming device and process. (3) It has suitable stiffness and curling performance, so it has good elasticity and opening property, and when the tow loading is relatively small, by adding plasticizer or adhesive, the filter rod can meet the requirements of certain hardness, drawing resistance and appearance quality, and has a relatively high rod production rate. (4) It has sufficient heat resistance, so that the filter tip will not be crushed or deformed during smoking of the cigarette. (5) It has relatively high filtering efficiency against harmful components in smoke. (6) It does not affect the sensory quality of the cigarette. Therefore, it is necessary to develop dedicated spinning and post-processing process technology to meet the requirements for cigarettes.

[0004] For example, the Chinese invention patent CN103074716A relates to a polylactic acid cigarette tow and filter rod with a skin-core structure and a manufacturing method thereof. The single fiber in the tow has a skin-core structure composed of an inner core and an outer skin, the resins of the main body of the skin layer and the core layer are both polylactic acid, the weight ratio of the skin layer resin to the core layer resin is 20:80-40:60, the crystallinity of the skin layer and the core layer of the tow is 3-25% and 25-60%, respectively, and the melting points of the skin layer and the core layer are 120-150°C and 150-175°C, respectively. The above invention combines the advantages of both the core layer and the skin layer, the core layer provides relatively high physical mechanical performance and heat resistance, and the skin layer provides good adhesiveness. The filter rod can be easily molded using common plasticizers (such as glycerol triacetate). Furthermore, the polylactic acid tow having a skin-core structure provided by the above invention has both a core layer and a skin layer that have good biodegradability, making it an environmentally friendly tobacco tow.

[0005] However, in the above-mentioned filter rod manufacturing structure, the skin layer resin and the core layer resin are both compositely spun from various raw materials, and the properties of the polylactic acid raw materials are not controlled. The crystallinity differences of the various raw materials, and the positions and numbers of the tow nodes are relatively large, so that the processing process of the polylactic acid tow with the above-mentioned skin-core structure is unstable.

[0006] In order to solve the above problems, it is necessary to design a rational and efficient group-processed polylactic acid fiber filter rod. Summary of the Invention

[0007] The objective of the present invention is to provide a polylactic acid fiber filter rod processed in groups, which is easy to install, and by strictly controlling the properties of the polylactic acid raw material, all the outer layer skins have a uniform crystallinity, all the inner layer cores also have a uniform crystallinity, and when the tow crystallizes, the nodes are evenly distributed, and the inside and outside of the produced polylactic acid fiber filter rod have a gradual crystallinity, and the processing process is more stable.

[0008] In order to achieve the above objectives, the present invention is realized by using the following technical solutions. A polylactic acid fiber filter rod processed in a group, comprising an inner core and an outer skin disposed on the outside of the inner core, the inner core and the outer skin are both composed of a plurality of polylactic acid fiber tows, the polylactic acid fiber tows of the inner core are made of a first component raw material, the polylactic acid fiber tows of the outer skin are made of a second component raw material, the content of L-lactic acid monomer in the first component raw material is higher than that in the second component raw material, a dispersant is added to the first component raw material, glycerol triacetate is added to the second component raw material, and the polylactic acid fiber tows of the inner core are induced to generate crystals by draft stress so as to improve the crystallinity of the polylactic acid fiber tows of the inner core.

[0009] In a preferred embodiment of the present invention, the ratio of the number of polylactic acid fiber tows in the inner core layer and the outer skin layer is in the range of 30:70 to 35:65.

[0010] In a preferred embodiment of the present invention, a nucleating agent is added to both the first component raw material and the second component raw material, and the content of the nucleating agent in the first component raw material is equal to or greater than the content of the nucleating agent in the second component raw material.

[0011] In a preferred embodiment of the present invention, a transition layer is provided between the inner core and the outer skin, the transition layer is composed of a plurality of polylactic acid fiber tows, and the content of L-lactic acid monomer in the component raw material used for the polylactic acid fiber tow of the transition layer is equal to or less than the content of L-lactic acid monomer in the first component raw material and equal to or more than the content of L-lactic acid monomer in the second component raw material.

[0012] In a preferred embodiment of the present invention, the number of the transition layers is at least two, and the content of L-lactic acid monomer in the component raw materials used for the polylactic acid fiber tow of the transition layer close to the inner core is equal to or greater than the content of L-lactic acid monomer in the component raw materials used for the polylactic acid fiber tow of the transition layer close to the outer skin.

[0013] In a preferred embodiment of the present invention, a nucleating agent is also added to the component raw material used for the polylactic acid fiber tow of the transition layer, and the content of the nucleating agent in the component raw material is less than or equal to the content of the nucleating agent in the first component raw material and is greater than or equal to the content of the nucleating agent in the second component raw material.

[0014] In a preferred embodiment of the present invention, an acetate fiber tow layer is provided on the outside of the outer skin.

[0015] The present invention relates to a method for producing a group processed polylactic acid fiber filter rod, comprising the steps of: S1: Obtaining polylactic acid having a first predetermined content of L-racemate, adding a dispersant to obtain a first component raw material, and crystallization is induced by draft stress during spinning of the first component raw material to obtain a first polylactic acid fiber tow; S2: Obtaining polylactic acid having a second predetermined value of L-racemic content lower than the first predetermined value, adding glycerol triacetate to obtain a second component raw material, and spinning the second component raw material into a second polylactic acid fiber tow; S3: combining a plurality of first polylactic acid fiber tows to form an inner layer core, combining a plurality of second polylactic acid fiber tows to form an outer layer skin, and covering the outside of the inner layer core with the outer layer skin to form a polylactic acid fiber filter rod having a skin-core structure.

[0016] In a preferred embodiment of the present invention, before performing step S3, a polylactic acid having a third predetermined content of L-racemate is obtained, a third polylactic acid fiber tow is obtained, and a plurality of the third polylactic acid fiber tows are combined to form a transition layer; When performing step S3, the transition layer covers the outside of the inner core, and the outer skin covers the outside of the transition layer.

[0017] In a preferred embodiment of the present invention, after step S3 is performed, the outside of the outer skin is covered with an acetate fiber tow layer.

[0018] The beneficial effects of the polylactic acid fiber filter rod processed by the group of the present invention and its manufacturing method are that it is easy to install, and by strictly controlling the properties of the polylactic acid raw material, all the outer layer skins have a uniform crystallinity, all the inner layer cores also have a uniform crystallinity, and when the tow crystallizes, the nodes are evenly distributed, and the inner and outer sides of the manufactured polylactic acid fiber filter rod have gradual crystallinity, and the processing process is more stable. [Brief description of the drawings]

[0019] In the figure: 1, inner core; 2, outer skin; 3, transition layer; 4, acetate fiber tow layer. [Figure 1] FIG. 2 is a cross-sectional view of one embodiment of a polylactic acid fiber filter rod fabricated with groups according to the present invention. [Diagram 2] 1 is a flow chart of a method for producing a group processed polylactic acid fiber filter rod according to the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0020] The following are specific examples of the present invention to further illustrate the technical solutions of the present invention, but the present invention is not limited to these examples.

[0021] Various exemplary embodiments of the present invention will now be described in detail with reference to the drawings. It should be noted that unless otherwise specified, the relative arrangement and steps of modules and steps described in these embodiments do not limit the scope of the present invention.

[0022] At the same time, for ease of explanation, the processes in the drawings should be understood as being not performed in isolation, but as multiple steps intersecting with each other.

[0023] In the description of the present invention, it should be explained that the directions or positional relationships indicated by terms such as "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", and "outer" are those shown in the drawings or those customarily arranged when the product of the present invention is used, and are merely for facilitating and simplifying the description of the present invention, and do not indicate or suggest that the devices or elements mentioned have a specific direction or must be constructed and operated in a specific direction, and therefore should not be understood as limiting the present invention. Furthermore, terms such as "first", "second", and the like are used only to distinguish the description, and are not understood as indicating or suggesting relative importance.

[0024] The following description of at least one exemplary embodiment is merely illustrative in nature and is not intended to be in any way limiting of the invention and its application or uses.

[0025] Techniques, methods and systems known to those skilled in the art may not be discussed in detail, but where appropriate, the techniques, methods and systems should be considered as part of this specification.

[0026] Example 1: As shown in FIG. 1, a polylactic acid fiber filter rod processed in groups, comprising an inner core 1 and an outer skin 2 disposed on the outside of the inner core 1, the inner core 1 and the outer skin 2 are both composed of a plurality of polylactic acid fiber tows, the polylactic acid fiber tows of the inner core 1 are made of a first component raw material, the polylactic acid fiber tows of the outer skin 2 are made of a second component raw material, the content of L-lactic acid monomer in the first component raw material is higher than that in the second component raw material, and a dispersant is added to the first component raw material, and glycerol triacetate is added to the second component raw material, and the polylactic acid fiber tows of the inner core 1 are induced to generate crystals by draft stress, so as to improve the crystallinity of the polylactic acid fiber tows of the inner core 1.

[0027] In the present invention, polylactic acid having a first predetermined content of L-racemate is obtained, and a dispersant is added to obtain a first component raw material. During spinning of the first component raw material, crystallization is induced by draft stress to obtain a first polylactic acid fiber tow, so that the first polylactic acid fiber tow has a higher crystallinity and provides relatively high physical-mechanical properties and heat resistance. By adding a dispersant, the first polylactic acid fiber tow with high crystallinity is less likely to have large nodes and is easier to slit.

[0028] Generally, the range of the first predetermined value is 95% to 98%, that is, the first component raw material contains 95% to 98% L-racemate (i.e., L-lactic acid monomer). With such a high content of L-racemate, the melting point of the first polylactic acid fiber tow is also high, and in the spinning and post-processing process, low-temperature crystallization is induced by draft stress, improving the tow crystallinity after drafting, improving the thermal stability of the tow size, and making it easy to curl and shape, ensuring that the tow has suitable rigidity and curling performance, as well as good elasticity and openability, and relatively low thermal shrinkage performance.

[0029] Similarly, polylactic acid having a second predetermined value of L-racemate content lower than the first predetermined value is obtained, glycerol triacetate is added to obtain a second component raw material, and the second component raw material is spun into a second polylactic acid fiber tow, so that the second polylactic acid fiber tow has a slightly lower crystallinity than the first polylactic acid fiber tow, but provides more swelling and adhesive properties by adding glycerol triacetate.

[0030] The second predetermined value is equal to or less than the first predetermined value. Generally, the second predetermined value is in the range of 92% to 95%, and the second component raw material needs to contain 92% to 95% L-racemate, and glycerol triacetate is added to the second component raw material. Under the action of glycerol triacetate, the second polylactic acid fiber tow swells and becomes sticky, and finally, by combining with the first polylactic acid fiber tow obtained from the first component raw material, a polylactic acid tow with a skin-core structure and good adhesion can be obtained.

[0031] Finally, a plurality of first polylactic acid fiber tows are combined to form an inner layer core, a plurality of second polylactic acid fiber tows are combined to form an outer layer skin, and the outer layer skin is used to cover the outside of the inner layer core, thereby forming a polylactic acid fiber filter rod having a skin-core structure.

[0032] Here, the ratio range of the number of polylactic acid fiber tows in the inner core layer 1 and the outer skin layer 2 is between 30:70 and 35:65, that is, the mass ratio of the core to the skin is within this range.

[0033] It should be noted that for polylactic acid fiber filter rods produced in the same batch, all the first component raw materials have the same origin, batch and purification steps. For polylactic acid fiber filter rods produced in the same batch, all the second component raw materials have the same origin, batch and purification steps.

[0034] It can also be seen that in one polylactic acid filter rod or in a batch of polylactic acid filter rods produced at the same time, all the first polylactic acid fiber tows produced have the same properties, the crystallinity of all the first polylactic acid fiber tows produced is uniformly distributed, and is less likely to produce relatively large agglomerates and cause impact and damage to the alloy knife during slitting, and the properties of all the second polylactic acid fiber tows are also the same.

[0035] In this way, by strictly controlling the properties of the polylactic acid raw material, all the outer skin layers have a uniform crystallinity, and all the inner core layers also have a uniform crystallinity, and when the tow crystallizes, the nodes are evenly distributed, and the processing process is more stable.

[0036] And the crystallinity of the first polylactic acid fiber tow is higher than that of the second polylactic acid fiber tow, so that the inside and outside of the produced polylactic acid fiber filter rod have gradual crystallinity, and the multi-layer structure is processed in groups.

[0037] Here, the following meaning is expanded: the raw materials of the polylactic acid fiber tow of the inner core and the outer skin need to be from the same place of origin, batch and purification step, that is, to ensure the uniqueness, so under the premise that the tobacco factory purchases two kinds of raw materials at the same time, if they cannot be mixed and processed, the two kinds of raw materials can be directly produced on two different production lines to obtain two different kinds of polylactic acid fiber tow, and based on the comparison of the L-lactic acid monomer content of the two kinds of raw materials, the raw material with a high content of L-lactic acid monomer is produced according to the production method of the inner core, and the raw material with a low content of L-lactic acid monomer is produced according to the production method of the outer skin, and finally the inner and outer distribution of the two kinds of polylactic acid fiber tows are combined, not only to achieve the uniqueness of the raw material of a single layer, but also to meet the crystallinity gradation between the inner and outer sides.

[0038] The polylactic acid fiber filter rod processed by the group of the present invention is easy to install, and the properties of the polylactic acid raw material are strictly controlled, so that all the outer skin layers have a uniform crystallinity, all the inner core layers also have a uniform crystallinity, and when the tow crystallizes, the nodes are evenly distributed, and the inner and outer sides of the produced polylactic acid fiber filter rod have gradually changing crystallinity, and the processing process is more stable.

[0039] Example 2: As shown in FIG. 1, this is still only one embodiment of the present invention. Based on Example 1, in the polylactic acid fiber filter rod processed by the group of the present invention, the first component raw material and the second component raw material are both added with nucleating agent, and the content of the nucleating agent in the first component raw material is equal to or greater than the content of the nucleating agent in the second component raw material, so as to further increase the gradation of crystallinity between the inside and outside of the polylactic acid fiber filter rod.

[0040] Furthermore, a transition layer 3 is provided between the inner core 1 and the outer skin 2, and the transition layer is composed of a plurality of polylactic acid fiber tows. The content of L-lactic acid monomer in the component raw material used for the polylactic acid fiber tow of the transition layer 3 is equal to or less than the content of L-lactic acid monomer in the first component raw material and equal to or more than the content of L-lactic acid monomer in the second component raw material.

[0041] In practice, the number of the transition layers 3 is at least two, and the content of L-lactic acid monomer in the component raw materials used for the polylactic acid fiber tow of the transition layer 3 close to the inner core layer 1 is equal to or greater than the content of L-lactic acid monomer in the component raw materials used for the polylactic acid fiber tow of the transition layer 3 close to the outer skin layer 2.

[0042] The multiple transition layers 3 are all processed in groups, and various raw materials are processed in multiple production lines to form polylactic acid fiber tows, which can then be coated layer by layer based on the relationship of the L-lactic acid monomer content.

[0043] In addition, a nucleating agent is also added to the component raw material used for the polylactic acid fiber tow of the transition layer 3, and the content of the nucleating agent in the component raw material is less than or equal to the content of the nucleating agent in the first component raw material and greater than or equal to the content of the nucleating agent in the second component raw material. In the case of multiple transition layers, the closer to the inside, the more nucleating agent is added to the component raw material used for the polylactic acid fiber tow of the transition layer 3.

[0044] Finally, an acetate fiber tow layer is installed on the outside of the outer skin 2, that is, the outside of the polylactic acid fiber tow filter rod is coated with an acetate fiber tow outer layer. By utilizing the adhesive effect and adsorption performance of the acetate fiber tow layer, the stability of the filter rod structure is improved and the adsorption performance of the filter rod is ensured.

[0045] Example 3: As shown in FIG. 2, the present invention provides a method for producing a polylactic acid fiber filter rod processed in the above group of examples, S1: Obtaining polylactic acid having a first predetermined content of L-racemate, adding a dispersant to obtain a first component raw material, and crystallization is induced by draft stress during spinning of the first component raw material to obtain a first polylactic acid fiber tow; S2: Obtaining polylactic acid having a second predetermined value of L-racemic content lower than the first predetermined value, adding glycerol triacetate to obtain a second component raw material, and spinning the second component raw material into a second polylactic acid fiber tow; S3: combining a plurality of first polylactic acid fiber tows to form an inner layer core, combining a plurality of second polylactic acid fiber tows to form an outer layer skin, and covering the outside of the inner layer core with the outer layer skin to form a polylactic acid fiber filter rod having a skin-core structure.

[0046] Before performing step S3, obtain polylactic acid having a third predetermined value of L-racemic content, obtain a third polylactic acid fiber tow, and combine a plurality of the third polylactic acid fiber tows to form a transition layer; When performing step S3, the transition layer covers the outside of the inner core, and the outer skin covers the outside of the transition layer.

[0047] After performing step S3, the outside of the outer skin is covered with an acetate fiber tow layer.

[0048] The polylactic acid fiber filter rod processed by the group of the present invention and its manufacturing method are easy to install, and by strictly controlling the properties of the polylactic acid raw material, all the outer layer skins have a uniform crystallinity, all the inner layer cores also have a uniform crystallinity, and when the tow crystallizes, the nodes are evenly distributed, and the inner and outer sides of the manufactured polylactic acid fiber filter rod have gradually changing crystallinity, the processing process is more stable, and the adsorption performance of the filter rod is ensured.

[0049] The present invention is not limited to the above specific embodiments, and various modifications and variations are possible in the present invention. Any modifications, equivalent replacements, improvements, etc. made to the above embodiments based on the technical essence of the present invention should be included in the scope of the claims of the present invention.

Claims

1. A polylactic acid fiber filter rod processed in groups, comprising an inner core (1) and an outer skin (2) disposed on the outside of the inner core (1), the inner core (1) and the outer skin (2) are both composed of a plurality of polylactic acid fiber tows, the polylactic acid fiber tows in the inner core (1) are manufactured from a first component raw material, the polylactic acid fiber tows in the outer skin (2) are manufactured from a second component raw material, the content of L-lactic acid monomer in the first component raw material is higher than the content of L-lactic acid monomer in the second component raw material, a dispersant is added to the first component raw material, glycerol triacetate is added to the second component raw material, and the polylactic acid fiber tows in the inner core (1) are induced to generate crystals by draft stress so as to improve the crystallinity of the polylactic acid fiber tows in the inner core (1).

2. The polylactic acid fiber filter rod processed according to the group of claims 1, characterized in that the ratio range of the number of polylactic acid fiber tows in the inner core (1) and the outer skin (2) is between 30:70 and 35:

65.

3. The polylactic acid fiber filter rod processed according to claim 1, characterized in that the first component raw material and the second component raw material are both added with a nucleating agent, and the content of the nucleating agent in the first component raw material is equal to or greater than the content of the nucleating agent in the second component raw material.

4. The polylactic acid fiber filter rod processed according to the group according to claim 1, characterized in that a transition layer (3) is installed between the inner core (1) and the outer skin (2), the transition layer is composed of a plurality of polylactic acid fiber tows, and the content of L-lactic acid monomer in the component raw material used for the polylactic acid fiber tow of the transition layer (3) is less than or equal to the content of L-lactic acid monomer in the first component raw material and is greater than or equal to the content of L-lactic acid monomer in the second component raw material.

5. The polylactic acid fiber filter rod processed according to the group according to claim 4, characterized in that the number of the transition layers (3) is at least two, and the content of L-lactic acid monomer in the component raw materials used for the polylactic acid fiber tow of the transition layer (3) close to the inner core (1) is equal to or greater than the content of L-lactic acid monomer in the component raw materials used for the polylactic acid fiber tow of the transition layer (3) close to the outer skin (2).

6. The polylactic acid fiber filter rod processed according to the group of claims 4, characterized in that the component raw material used for the polylactic acid fiber tow of the transition layer (3) also contains a nucleating agent, and the content of the nucleating agent in the component raw material is less than or equal to the content of the nucleating agent in the first component raw material and is greater than or equal to the content of the nucleating agent in the second component raw material.

7. 2. A polylactic acid fiber filter rod made according to the group of claims 1, characterized in that an acetate fiber tow layer (4) is provided on the outside of the outer skin (2).

8. A method for producing a polylactic acid fiber filter rod processed with the group according to any one of claims 1 to 7, comprising the steps of: S1: obtaining polylactic acid having a first predetermined content of L-racemate, adding a dispersant to obtain a first component raw material, and inducing crystallization of the first component raw material by draft stress during spinning to obtain a first polylactic acid fiber tow; S2: obtaining polylactic acid having a second predetermined value of L-racemic content lower than the first predetermined value, adding glycerol triacetate to obtain a second component raw material, and spinning the second component raw material into a second polylactic acid fiber tow; S3: forming an inner layer core by combining a plurality of first polylactic acid fiber tows, forming an outer layer skin by combining a plurality of second polylactic acid fiber tows, and covering the outside of the inner layer core with the outer layer skin to form a polylactic acid fiber filter rod having a skin-core structure.

9. Before performing step S3, obtain polylactic acid having a third predetermined value of L-racemic content, obtain a third polylactic acid fiber tow, and combine a plurality of the third polylactic acid fiber tows to form a transition layer; The method for producing a polylactic acid fiber filter rod processed in the group according to claim 8, characterized in that, when performing step S3, the transition layer covers the outside of the inner core, and the outer skin covers the outside of the transition layer.

10. The method for producing a polylactic acid fiber filter rod processed in the group according to claim 8, characterized in that after performing step S3, the outside of the outer layer skin is covered with an acetate fiber tow layer.

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