CN112521735A - PLA heat-resistant straw and preparation method thereof - Google Patents
PLA heat-resistant straw and preparation method thereof Download PDFInfo
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- CN112521735A CN112521735A CN202011188754.6A CN202011188754A CN112521735A CN 112521735 A CN112521735 A CN 112521735A CN 202011188754 A CN202011188754 A CN 202011188754A CN 112521735 A CN112521735 A CN 112521735A
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- 239000010902 straw Substances 0.000 title claims abstract description 67
- 238000002360 preparation method Methods 0.000 title claims abstract description 10
- 239000004626 polylactic acid Substances 0.000 claims abstract description 93
- 229920000747 poly(lactic acid) Polymers 0.000 claims abstract description 91
- 238000001125 extrusion Methods 0.000 claims abstract description 51
- 229920003232 aliphatic polyester Polymers 0.000 claims abstract description 13
- 239000000314 lubricant Substances 0.000 claims abstract description 9
- 239000002667 nucleating agent Substances 0.000 claims abstract description 9
- 125000003118 aryl group Chemical group 0.000 claims abstract description 8
- 239000011256 inorganic filler Substances 0.000 claims abstract description 8
- 229910003475 inorganic filler Inorganic materials 0.000 claims abstract description 8
- 229920000728 polyester Polymers 0.000 claims abstract description 8
- YXFVVABEGXRONW-UHFFFAOYSA-N Toluene Chemical compound CC1=CC=CC=C1 YXFVVABEGXRONW-UHFFFAOYSA-N 0.000 claims description 30
- 238000001816 cooling Methods 0.000 claims description 29
- 239000000463 material Substances 0.000 claims description 27
- 238000003756 stirring Methods 0.000 claims description 25
- -1 aromatic hydroxy acid Chemical class 0.000 claims description 23
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 20
- JVTAAEKCZFNVCJ-UHFFFAOYSA-N lactic acid Chemical compound CC(O)C(O)=O JVTAAEKCZFNVCJ-UHFFFAOYSA-N 0.000 claims description 16
- 239000000203 mixture Substances 0.000 claims description 15
- 238000002156 mixing Methods 0.000 claims description 10
- XQXPVVBIMDBYFF-UHFFFAOYSA-N 4-hydroxyphenylacetic acid Chemical compound OC(=O)CC1=CC=C(O)C=C1 XQXPVVBIMDBYFF-UHFFFAOYSA-N 0.000 claims description 8
- 239000004310 lactic acid Substances 0.000 claims description 8
- 235000014655 lactic acid Nutrition 0.000 claims description 8
- 238000002844 melting Methods 0.000 claims description 8
- 230000008018 melting Effects 0.000 claims description 8
- 238000005520 cutting process Methods 0.000 claims description 7
- 238000000034 method Methods 0.000 claims description 7
- FJKROLUGYXJWQN-UHFFFAOYSA-N 4-hydroxybenzoic acid Chemical compound OC(=O)C1=CC=C(O)C=C1 FJKROLUGYXJWQN-UHFFFAOYSA-N 0.000 claims description 6
- FPAFDBFIGPHWGO-UHFFFAOYSA-N dioxosilane;oxomagnesium;hydrate Chemical compound O.[Mg]=O.[Mg]=O.[Mg]=O.O=[Si]=O.O=[Si]=O.O=[Si]=O.O=[Si]=O FPAFDBFIGPHWGO-UHFFFAOYSA-N 0.000 claims description 6
- 239000000178 monomer Substances 0.000 claims description 6
- 229940090248 4-hydroxybenzoic acid Drugs 0.000 claims description 3
- 239000011521 glass Substances 0.000 claims description 3
- 238000010438 heat treatment Methods 0.000 claims description 3
- NMHMNPHRMNGLLB-UHFFFAOYSA-N phloretic acid Chemical compound OC(=O)CCC1=CC=C(O)C=C1 NMHMNPHRMNGLLB-UHFFFAOYSA-N 0.000 claims description 3
- 238000006116 polymerization reaction Methods 0.000 claims description 3
- 239000011324 bead Substances 0.000 claims description 2
- 239000003054 catalyst Substances 0.000 claims description 2
- 150000001875 compounds Chemical class 0.000 claims description 2
- 239000010459 dolomite Substances 0.000 claims description 2
- 229910000514 dolomite Inorganic materials 0.000 claims description 2
- RKISUIUJZGSLEV-UHFFFAOYSA-N n-[2-(octadecanoylamino)ethyl]octadecanamide Chemical compound CCCCCCCCCCCCCCCCCC(=O)NCCNC(=O)CCCCCCCCCCCCCCCCC RKISUIUJZGSLEV-UHFFFAOYSA-N 0.000 claims description 2
- 238000005453 pelletization Methods 0.000 claims description 2
- 229920002961 polybutylene succinate Polymers 0.000 claims description 2
- 239000004631 polybutylene succinate Substances 0.000 claims description 2
- 229920009537 polybutylene succinate adipate Polymers 0.000 claims description 2
- 239000004630 polybutylene succinate adipate Substances 0.000 claims description 2
- 239000003607 modifier Substances 0.000 claims 1
- 238000005516 engineering process Methods 0.000 abstract description 6
- 235000013305 food Nutrition 0.000 abstract description 6
- 235000012171 hot beverage Nutrition 0.000 abstract description 6
- 238000004519 manufacturing process Methods 0.000 abstract description 6
- 238000005336 cracking Methods 0.000 abstract 1
- 239000000498 cooling water Substances 0.000 description 8
- 238000012545 processing Methods 0.000 description 7
- 239000004743 Polypropylene Substances 0.000 description 5
- 229920001155 polypropylene Polymers 0.000 description 5
- 230000009471 action Effects 0.000 description 4
- 238000006243 chemical reaction Methods 0.000 description 4
- 238000003760 magnetic stirring Methods 0.000 description 4
- 229920001896 polybutyrate Polymers 0.000 description 4
- 238000005406 washing Methods 0.000 description 4
- 230000000052 comparative effect Effects 0.000 description 3
- 229920003023 plastic Polymers 0.000 description 3
- 239000004033 plastic Substances 0.000 description 3
- CURLTUGMZLYLDI-UHFFFAOYSA-N Carbon dioxide Chemical compound O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 description 2
- 239000004698 Polyethylene Substances 0.000 description 2
- 230000007547 defect Effects 0.000 description 2
- 230000009477 glass transition Effects 0.000 description 2
- 229920000573 polyethylene Polymers 0.000 description 2
- 239000002994 raw material Substances 0.000 description 2
- 229930182843 D-Lactic acid Natural products 0.000 description 1
- JVTAAEKCZFNVCJ-UWTATZPHSA-N D-lactic acid Chemical compound C[C@@H](O)C(O)=O JVTAAEKCZFNVCJ-UWTATZPHSA-N 0.000 description 1
- 240000008042 Zea mays Species 0.000 description 1
- 235000005824 Zea mays ssp. parviglumis Nutrition 0.000 description 1
- 235000002017 Zea mays subsp mays Nutrition 0.000 description 1
- 230000004075 alteration Effects 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 239000001569 carbon dioxide Substances 0.000 description 1
- 229910002092 carbon dioxide Inorganic materials 0.000 description 1
- 239000003086 colorant Substances 0.000 description 1
- 238000009264 composting Methods 0.000 description 1
- 238000007334 copolymerization reaction Methods 0.000 description 1
- 235000005822 corn Nutrition 0.000 description 1
- 230000002596 correlated effect Effects 0.000 description 1
- 238000002425 crystallisation Methods 0.000 description 1
- 230000008025 crystallization Effects 0.000 description 1
- 229940022769 d- lactic acid Drugs 0.000 description 1
- 238000013461 design Methods 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 238000003912 environmental pollution Methods 0.000 description 1
- 238000009472 formulation Methods 0.000 description 1
- 239000007789 gas Substances 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- VUZPPFZMUPKLLV-UHFFFAOYSA-N methane;hydrate Chemical compound C.O VUZPPFZMUPKLLV-UHFFFAOYSA-N 0.000 description 1
- 230000005012 migration Effects 0.000 description 1
- 238000013508 migration Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 238000000465 moulding Methods 0.000 description 1
- 239000000123 paper Substances 0.000 description 1
- 239000003208 petroleum Substances 0.000 description 1
- 125000001997 phenyl group Chemical group [H]C1=C([H])C([H])=C(*)C([H])=C1[H] 0.000 description 1
- 229920001707 polybutylene terephthalate Polymers 0.000 description 1
- 229920000642 polymer Polymers 0.000 description 1
- 239000002861 polymer material Substances 0.000 description 1
- 230000008569 process Effects 0.000 description 1
- 238000012797 qualification Methods 0.000 description 1
- 238000007670 refining Methods 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
- XTQHKBHJIVJGKJ-UHFFFAOYSA-N sulfur monoxide Chemical class S=O XTQHKBHJIVJGKJ-UHFFFAOYSA-N 0.000 description 1
- 229910052815 sulfur oxide Inorganic materials 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
- C08L67/00—Compositions of polyesters obtained by reactions forming a carboxylic ester link in the main chain; Compositions of derivatives of such polymers
- C08L67/04—Polyesters derived from hydroxycarboxylic acids, e.g. lactones
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C48/00—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor
- B29C48/022—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor characterised by the choice of material
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C48/00—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor
- B29C48/03—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor characterised by the shape of the extruded material at extrusion
- B29C48/09—Articles with cross-sections having partially or fully enclosed cavities, e.g. pipes or channels
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C48/00—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor
- B29C48/16—Articles comprising two or more components, e.g. co-extruded layers
- B29C48/18—Articles comprising two or more components, e.g. co-extruded layers the components being layers
- B29C48/21—Articles comprising two or more components, e.g. co-extruded layers the components being layers the layers being joined at their surfaces
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B1/00—Layered products having a non-planar shape
- B32B1/08—Tubular products
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B27/00—Layered products comprising a layer of synthetic resin
- B32B27/06—Layered products comprising a layer of synthetic resin as the main or only constituent of a layer, which is next to another layer of the same or of a different material
- B32B27/08—Layered products comprising a layer of synthetic resin as the main or only constituent of a layer, which is next to another layer of the same or of a different material of synthetic resin
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B27/00—Layered products comprising a layer of synthetic resin
- B32B27/36—Layered products comprising a layer of synthetic resin comprising polyesters
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B2307/00—Properties of the layers or laminate
- B32B2307/30—Properties of the layers or laminate having particular thermal properties
- B32B2307/306—Resistant to heat
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B2307/00—Properties of the layers or laminate
- B32B2307/30—Properties of the layers or laminate having particular thermal properties
- B32B2307/308—Heat stability
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B2307/00—Properties of the layers or laminate
- B32B2307/70—Other properties
- B32B2307/732—Dimensional properties
- B32B2307/734—Dimensional stability
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
- C08L2201/00—Properties
- C08L2201/08—Stabilised against heat, light or radiation or oxydation
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- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
- C08L2203/00—Applications
- C08L2203/18—Applications used for pipes
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- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
- C08L2205/00—Polymer mixtures characterised by other features
- C08L2205/02—Polymer mixtures characterised by other features containing two or more polymers of the same C08L -group
- C08L2205/025—Polymer mixtures characterised by other features containing two or more polymers of the same C08L -group containing two or more polymers of the same hierarchy C08L, and differing only in parameters such as density, comonomer content, molecular weight, structure
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- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
- C08L2205/00—Polymer mixtures characterised by other features
- C08L2205/03—Polymer mixtures characterised by other features containing three or more polymers in a blend
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- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Chemical & Material Sciences (AREA)
- Health & Medical Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Medicinal Chemistry (AREA)
- Polymers & Plastics (AREA)
- Organic Chemistry (AREA)
- Compositions Of Macromolecular Compounds (AREA)
- Biological Depolymerization Polymers (AREA)
Abstract
The PLA heat-resistant straw is prepared by adopting a three-layer co-extrusion technology, and comprises an outer layer, a middle layer and an inner layer which are sequentially connected, wherein the outer layer and the inner layer comprise the following components in parts by weight: 36 to 73 portions of copolymerized polylactic acid, 10 to 20 portions of aromatic polyester, 10 to 20 portions of aliphatic polyester, 5 to 20 portions of inorganic filler, 1 to 2 portions of polylactic acid nucleating agent and 1 to 2 portions of lubricant; the intermediate layer is made of aliphatic polyester. The straw has good heat resistance, reaches the level of above 120 ℃, meets the requirements of a hot drink straw, and is prepared by adopting a three-layer co-extrusion technology, so that the straw is stable and efficient in production and preparation, free from cracking of a notch, stable in size performance, and safe in food, and meets the requirements of hot drinks.
Description
Technical Field
The invention relates to the technical field of high polymer materials, in particular to a PLA heat-resistant suction pipe.
Background
The straw is a cylindrical hollow tube body and is mainly used for absorbing liquid. The common materials for preparing the suction pipe at present comprise paper, plastic, metal, glass and the like. Plastic straws are available in a large number in the market because of their wide processing range, various shapes and various colors. Today, in the environment and sustainable development, the traditional polypropylene straw has been gradually replaced by biodegradable materials due to serious environmental pollution. At present, the common biodegradable material is polylactic acid (PLA), and polylactic acid products can be naturally decomposed into carbon dioxide and water under the composting condition, so that the pollution of the traditional polypropylene (PP) plastic products to the environment is greatly reduced. And different from petrochemical products such as polypropylene (PP), Polyethylene (PE) and the like, the raw materials for producing polylactic acid are mainly natural raw materials such as corn and the like, so that the dependence on petroleum resources is reduced, and the emission of pollution gases such as nitric oxides, sulfur oxides and the like in the original oil refining process and the like is also reduced.
However, the polylactic acid straw also has the defects that firstly, the thermal deformation temperature of the polylactic acid is lower, about 58 ℃, the polylactic acid straw can deform when contacting with hot drinks during use, the requirement of the hot drinks cannot be met, and the modification for improving the heat resistance of the polylactic acid can cause the food safety of products to be unqualified and the migration to exceed the standard. Secondly, the pure polylactic acid material is hard and brittle, has poor toughness and can crack under the conditions of the existing straw processing equipment and processing technique.
Disclosure of Invention
In order to overcome the defects of the prior art, the invention provides the PLA heat-resistant straw which has better heat resistance reaching the level of more than 120 ℃ and meeting the requirements of hot drink straws, and meanwhile, the three-layer co-extrusion technology can realize stable forming processing production, no crack in a notch, stable dimensional performance and food safety and qualification.
In order to achieve the purpose, the heat-resistant PLA straw is prepared by adopting a three-layer co-extrusion technology, and comprises an outer layer, a middle layer and an inner layer which are sequentially connected, wherein the outer layer and the inner layer comprise the following components in parts by weight:
the intermediate layer is made of aliphatic polyester.
Furthermore, the viscosity average molecular weight of the copolymerized polylactic acid is more than or equal to 3 ten thousand, and the copolymerized polylactic acid is obtained by copolymerizing lactic acid and aromatic hydroxy acid, wherein the aromatic hydroxy acid comprises one or more of p-hydroxybenzoic acid, p-hydroxyphenylacetic acid and p-hydroxyphenylpropionic acid.
Further, the aromatic polyester comprises polybutylene terephthalate and/or polybutylene terephthalate succinate, and the aliphatic polyester of the inner layer, the outer layer and the middle layer comprises polybutylene succinate and/or polybutylene succinate adipate.
Further, the inorganic filler comprises one or more of talcum powder, dolomite and glass beads, and the mesh number of the inorganic filler is 2500 meshes.
Further, the polylactic acid nucleating agent comprises a hydrazide compound, and the lubricant comprises ethylene bis stearamide.
The invention also provides a preparation method of the PLA heat-resistant straw, which comprises the following steps:
s1: dissolving lactic acid and monomer aromatic hydroxy acid in toluene by using a vacuum stirring device, heating in an oil bath, adding a catalyst for polymerization to prepare copolymerized polylactic acid, and pelletizing for later use;
s2: sequentially adding copolymerized polylactic acid, aromatic polyester, aliphatic polyester, polylactic acid nucleating agent, lubricant and inorganic filler into a stirrer, and uniformly stirring;
s3: adding the mixture prepared in the step S2 into a double-screw extrusion device, and preparing a heat-resistant PLA modified material through melting, mixing, extruding, water cooling, air cooling, traction and grain cutting;
s4: adding the heat-resistant PLA modified material into the inner layer and the outer layer of the three-layer co-extrusion equipment, adding the aliphatic polyester into the middle layer of the three-layer co-extrusion equipment, and obtaining the finished product of the PLA heat-resistant straw through melting, extrusion, water cooling, air cooling, traction and dewatering.
Further, in step S1, the oil bath heating temperature is 140 ℃ to 160 ℃ and the polymerization time is 30 hours to 35 hours.
Further, in step S2, the stirring temperature is 80-100 ℃, the speed is 100-250 r/min, and the time is 10-15 min.
Further, in step S3, the extrusion temperature of the heat-resistant PLA modified material is 150 ℃ to 180 ℃, and the water cooling temperature is 20 ℃ to 30 ℃.
Further, in step S4, the PLA heat-resistant straw includes, in weight percent, an inner layer and an outer layer of 5%, an intermediate layer of 90%, an extrusion temperature of a pipe blank of the PLA heat-resistant straw is 170 to 200 ℃, a head temperature of the extruder is 180 to 200 ℃, and a water cooling temperature is 35 to 45 ℃.
According to the PLA heat-resistant straw, the benzene ring is introduced into the molecular structure of the biodegradable material D-lactic acid in a copolymerization mode, so that the glass transition temperature Tg of polylactic acid is increased, and the temperature resistance of the polylactic acid is further improved; aromatic polyester and aliphatic polyester are blended and added into biodegradable material polylactic acid, and amorphous modified crystalline polymer is utilized, so that the crystallization property and the processing property of the polylactic acid are improved, and the glass transition temperature and the thermal stability of the material are improved; meanwhile, the toughness of the straw in the cooling and cutting processes is improved, and the notch is prevented from being brittle; the added inorganic filler can effectively improve the strength and the dimensional stability of a thin-wall straw product (the wall thickness is less than 0.2 mm); the straw is processed by adopting three-layer co-extrusion equipment, so that the food safety and the heat resistance of the product can meet the requirements.
The heat-resistant PLA straw has the following beneficial effects: the heat resistance of the straw is effectively improved in the formula design, the temperature reaches the level above 120 ℃, the requirement of the hot drink straw is met, meanwhile, the three-layer co-extrusion technology is adopted, the stable forming processing production is facilitated, the notch is not cracked, the size performance is stable, and the food is safe and qualified.
Detailed Description
The technical solution of the present invention will be more clearly and completely explained by the description of the preferred embodiments of the present invention.
Example 1: PLA heat-resisting straw, including inlayer, intermediate level and skin, wherein inlayer and skin include:
the preparation process comprises the following steps:
s1: dissolving lactic acid and p-hydroxyphenylacetic acid in a toluene solution, setting the oil bath temperature to 150 ℃, adding the toluene solution added with the monomer into an oil bath magnetic stirring device, stirring and reacting for 30 hours, and washing and granulating the copolymerized polylactic acid obtained by the reaction for later use;
s2: mixing the materials according to a set proportion, adding the copolymerized polylactic acid, PBAT and PBS into a high-speed mixer, stirring at 80 ℃ and 100r/min, starting the equipment to stir for 3min, then sequentially adding talcum powder, a lubricant and a polylactic acid nucleating agent, and continuously stirring for 10min to form a mixture;
s3: the blend was added to a twin screw extrusion apparatus with the extrusion apparatus temperature set at 160 ℃ and the die head temperature (i.e., the extruder head temperature) set at 200 ℃. Starting equipment, and preparing the PLA heat-resistant modified material from the mixture through melting, mixing, extruding, water cooling, air cooling and granulating, wherein the temperature of cooling water is 30 ℃;
s4: adding a PLA heat-resistant modified material into an inner layer and an outer layer of three-layer co-extrusion straw extrusion equipment, adding PBA into a middle layer of the three-layer co-extrusion straw extrusion equipment, setting the temperature of the extrusion equipment to be 180 ℃, setting the temperature of a die head (namely the temperature of an extrusion head) to be 200 ℃, and forming straw products with various lengths by sequentially carrying out water cooling, air cooling, water removal and cutting on a pipe blank under the action of traction equipment, wherein the temperature of cooling water is 35 ℃.
Example 2: PLA heat-resisting straw, including inlayer, intermediate level and skin, wherein inlayer and skin include:
the preparation process comprises the following steps:
s1: dissolving lactic acid and p-hydroxybenzoic acid in a toluene solution, setting the oil bath temperature to 140 ℃, adding the toluene solution added with the monomer into an oil bath magnetic stirring device, stirring and reacting for 35 hours, and washing and granulating the copolymerized polylactic acid obtained by the reaction for later use;
s2: mixing the materials according to a set proportion, adding the copolymerized polylactic acid, PBAT and PBS into a high-speed mixer, stirring at 90 ℃ and 200r/min, starting the equipment to stir for 3min, then sequentially adding talcum powder, a lubricant and a polylactic acid nucleating agent, and continuously stirring for 10min to form a mixture;
s3: the blend was added to a twin screw extrusion apparatus with the extrusion apparatus temperature set at 170 ℃ and the die head temperature (i.e. the extruder head temperature) set at 200 ℃. Starting equipment, and preparing the PLA heat-resistant modified material from the mixture through melting, mixing, extruding, water cooling, air cooling and granulating, wherein the temperature of cooling water is 30 ℃;
s4: adding a PLA heat-resistant modified material into an inner layer and an outer layer of three-layer co-extrusion straw extrusion equipment, adding PBA into a middle layer of the three-layer co-extrusion straw extrusion equipment, setting the temperature of the extrusion equipment to be 190 ℃, setting the temperature of a die head (namely the temperature of an extruder head) to be 220 ℃, and forming straw products with various lengths by sequentially performing water cooling, air cooling, water removal and cutting on a pipe blank under the action of traction equipment, wherein the temperature of cooling water is 45 ℃.
Example 3: PLA heat-resisting straw, including inlayer, intermediate level and skin, wherein inlayer and skin include:
the preparation process comprises the following steps:
s1: dissolving lactic acid and p-hydroxyphenylacetic acid in a toluene solution, setting the oil bath temperature to 140 ℃, adding the toluene solution added with the monomer into an oil bath magnetic stirring device, stirring and reacting for 35 hours, and washing and granulating the copolymerized polylactic acid obtained by the reaction for later use;
s2: mixing the materials according to a set proportion, adding the copolymerized polylactic acid, PBAT and PBS into a high-speed mixer, stirring at 100 ℃ and 250r/min, starting the equipment to stir for 3min, then sequentially adding the talcum powder, the lubricant and the polylactic acid nucleating agent, and continuously stirring for 10min to form a mixture;
s3: the blend was added to a twin screw extrusion apparatus with the extrusion apparatus temperature set at 180 ℃ and the die head temperature (i.e. the extruder head temperature) set at 200 ℃. Starting equipment, and preparing the PLA heat-resistant modified material from the mixture through melting, mixing, extruding, water cooling, air cooling and granulating, wherein the temperature of cooling water is 30 ℃;
s4: adding a PLA heat-resistant modified material into an inner layer and an outer layer of three-layer co-extrusion straw extrusion equipment, adding polybutylene terephthalate adipate into a middle layer of the three-layer co-extrusion straw extrusion equipment, setting the temperature of the extrusion equipment to be 200 ℃, setting the temperature of a die head (namely the temperature of an extrusion head) to be 220 ℃, and forming straw products with various lengths by sequentially carrying out water cooling, air cooling, dewatering and cutting on a pipe blank under the action of traction equipment, wherein the temperature of cooling water is 45 ℃.
Example 4: PLA heat-resisting straw, including inlayer, intermediate level and skin, wherein inlayer and skin include:
the preparation process comprises the following steps:
s1: dissolving lactic acid and p-hydroxyphenylpropionic acid in a toluene solution, setting the oil bath temperature to 160 ℃, adding the toluene solution added with the monomer into an oil bath magnetic stirring device, stirring and reacting for 32 hours, and washing and granulating the copolymerized polylactic acid obtained by the reaction for later use;
s2: mixing the materials according to a set proportion, adding the copolymerized polylactic acid, PBAT and PBS into a high-speed mixer, stirring at the temperature of 95 ℃ and the stirring speed of 150r/min, starting the equipment for stirring for 3min, then sequentially adding the talcum powder, the lubricant and the polylactic acid nucleating agent, and continuously stirring for 10min to form a mixture;
s3: the blend was added to a twin screw extrusion apparatus with the extrusion apparatus temperature set at 190 ℃ and the die head temperature (i.e. the extruder head temperature) set at 200 ℃. Starting equipment, and preparing the PLA heat-resistant modified material from the mixture through melting, mixing, extruding, water cooling, air cooling and granulating, wherein the temperature of cooling water is 30 ℃;
s4: adding a PLA heat-resistant modified material into an inner layer and an outer layer of three-layer co-extrusion straw extrusion equipment, adding PBA into a middle layer of the three-layer co-extrusion straw extrusion equipment, setting the temperature of the extrusion equipment to be 200 ℃, setting the temperature of a die head (namely the temperature of an extrusion head) to be 220 ℃, and forming straw products with various lengths by sequentially carrying out water cooling, air cooling, water removal and cutting on a pipe blank under the action of traction equipment, wherein the temperature of cooling water is 40 ℃.
Comparative example 1: PLA heat-resistant straw, different from the PLA heat-resistant straw prepared in example 3, was: the inner and outer layer formulations used equal amounts of polylactic acid (PLA) instead of the copolymerized polylactic acid of example 1.
Comparative example 2: PLA heat-resistant straw, which is different from the PLA heat-resistant straw prepared in example 4, is: and respectively molding and processing the inner layer material, the outer layer material and the middle layer material by adopting a single-screw extruder.
The performance comparison of the heat-resistant suction pipes made of PLA obtained in examples 1 to 4 and comparative examples 1 to 2 is shown in Table 1.
Table 1: performance comparison of PLA heat-resistant straw
In conclusion, the copolymerized polylactic acid in the PLA heat-resistant straw can obviously improve the heat resistance of the straw, in addition, the heat resistance of the straw is positively correlated with the total content of the aromatic polyester and the aliphatic polyester, and the temperature resistance of the product can be adjusted by adjusting the content of the aromatic polyester and the aliphatic polyester.
The PLA heat-resistant straw can effectively realize the elasticity of straw products, avoids the occurrence of cracks when the products are cut, effectively improves the toughness of the traditional PLA straw products, can meet the requirements of normal production process, can also ensure the cup pricking and thermal deformation of the products, and adopts a three-layer co-extrusion technology in combination with the improvement of production equipment and production method to ensure the heat resistance and food safety of the products to meet the requirements.
The above detailed description merely describes preferred embodiments of the present invention and does not limit the scope of the invention. Without departing from the spirit and scope of the present invention, it should be understood that various changes, substitutions and alterations can be made herein by those skilled in the art without departing from the spirit and scope of the invention as defined by the appended claims. The scope of the invention is defined by the claims.
Claims (10)
1. The utility model provides a heat-resisting straw of PLA which characterized in that adopts three-layer coextrusion technique to extrude the preparation, and the straw is including the skin, intermediate level and the inlayer that connect gradually, skin and inlayer include the component of following part by weight:
the intermediate layer is made of aliphatic polyester.
2. The PLA heat-resistant straw as claimed in claim 1, wherein the viscosity average molecular weight of the copolymerized polylactic acid is not less than 3 ten thousand, the copolymerized polylactic acid is obtained by copolymerizing lactic acid and aromatic hydroxy acid, and the aromatic hydroxy acid comprises one or more of p-hydroxybenzoic acid, p-hydroxyphenylacetic acid and p-hydroxyphenylpropionic acid.
3. The PLA heat-resistant straw as claimed in claim 1, wherein the aromatic polyester comprises polybutylene terephthalate adipate and/or polybutylene terephthalate succinate, and the aliphatic polyesters of the inner layer, the outer layer and the middle layer comprise polybutylene succinate and/or polybutylene succinate adipate.
4. The PLA heat-resistant suction pipe as claimed in claim 1, wherein the inorganic filler comprises one or more of talcum powder, dolomite and glass beads, and the mesh number of the inorganic filler is 2500 meshes.
5. A PLA heat-resistant straw as in claim 1, wherein the polylactic acid nucleating agent comprises a hydrazide compound, and the lubricant comprises ethylene bis stearamide.
6. A preparation method of a PLA heat-resistant straw is characterized by comprising the following steps:
s1: dissolving lactic acid and monomer aromatic hydroxy acid in toluene by using a vacuum stirring device, heating in an oil bath, adding a catalyst for polymerization to prepare copolymerized polylactic acid, and pelletizing for later use;
s2: sequentially adding copolymerized polylactic acid, aromatic polyester, aliphatic polyester, polylactic acid nucleating agent, lubricant and inorganic filler into a stirrer, and uniformly stirring;
s3: adding the mixture prepared in the step S2 into a double-screw extrusion device, and preparing a heat-resistant PLA modified material through melting, mixing, extruding, water cooling, air cooling, traction and grain cutting;
s4: adding the heat-resistant PLA modified material into the inner layer and the outer layer of the three-layer co-extrusion equipment, adding the aliphatic polyester into the middle layer of the three-layer co-extrusion equipment, and obtaining the finished product of the PLA heat-resistant straw through melting, extrusion, water cooling, air cooling, traction and dewatering.
7. The method for preparing a heat-resistant PLA straw as claimed in claim 6, wherein in step S1, the oil bath is heated at 140 ℃ to 160 ℃ for 30h to 35 h.
8. The method for preparing a PLA heat-resistant straw as claimed in claim 6, wherein in step S2, the stirring temperature is 80-100 ℃, the stirring speed is 100-250 r/min, and the stirring time is 10-15 min.
9. The method for preparing a heat-resistant PLA straw as claimed in claim 6, wherein in step S3, the extrusion temperature of the heat-resistant PLA modifier is 150 ℃ to 180 ℃ and the water cooling temperature is 20 ℃ to 30 ℃.
10. The method for preparing a heat-resistant PLA straw as claimed in claim 6, wherein in step S4, the inner layer and the outer layer of the heat-resistant PLA straw are 5 wt% and the middle layer of the heat-resistant PLA straw is 90 wt%, the extrusion temperature of the blank of the heat-resistant PLA straw is 170-200 ℃, the temperature of the extrusion head is 180-200 ℃, and the water cooling temperature is 35-45 ℃.
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Application publication date: 20210319 |