A high and low temperature resistant coated baking paper and its production process

Abstract

This application discloses a high- and low-temperature resistant coated baking paper and its production process, comprising a blended coating layer and packaging paper, wherein the blended coating layer is located on one or both sides of the packaging paper; the blended coating layer comprises polypropylene and polytetrafluoroethylene in a mass ratio of 1:(0.08~0.12). Polytetrafluoroethylene, due to its special molecular structure, possesses excellent chemical stability and non-adhesive properties, which can effectively improve the barrier properties of the coated baking paper against moisture and oils, and maintain its performance stability over a very wide temperature range, thus meeting the high and low temperature resistance requirements of the coated baking paper. Simultaneously, during the production process, the packaging paper undergoes a pre-punching treatment to increase the actual contact area between the blended coating layer and the packaging paper, enhancing the mechanical interlocking effect between the two, thereby improving the interfacial bonding force between the blended coating layer and the packaging paper.

Description

Technical Field

[0001] This application relates to the field of coated paper, and in particular to a high and low temperature resistant coated baking paper and its production process. Background Technology

[0002] Laminated composite films are made by using materials such as PE (polyethylene), PP (polypropylene), or PET (polyethylene terephthalate) as a base material, which are then liquefied at high temperatures. This liquefied material is then coated onto the surface of substrates such as paper or non-woven fabric using a lamination machine. After cooling and curing, the liquid base material is uniformly and firmly bonded to the substrate, resulting in a tightly adhered film layer. This imparts waterproof, oil-proof, moisture-proof, and heat-sealing properties to the substrate. It is widely used in packaging, printing, medical, hygiene, protective, and industrial sheet materials, and can be used to produce various packaging boxes and bags, enhancing the protective and functional characteristics of products.

[0003] As a composite material of polymer resin and paper, coated paper can avoid direct contact between paper and food, thus ensuring food safety and hygiene. Among them, coated paper made of PP as the base material has excellent oil resistance and water resistance. However, PP has a relatively low load deformation temperature and insufficient high temperature rigidity. When applying this coated paper to the low temperature transportation and food heating fields of food packaging in a green and safe manner, it is necessary to innovate and optimize the composite technology of PP coated paper and the packaging sealing technology, improve the high and low temperature resistance, and expand the application range of coated paper. Summary of the Invention

[0004] To obtain a coated composite paper for use in low-temperature transportation, refrigeration, and microwave ovens, this application provides a high and low temperature resistant coated baking paper and its manufacturing process.

[0005] In a first aspect, this application provides a high and low temperature resistant coated baking paper, comprising a blended coated layer and packaging paper, wherein the blended coated layer is on one or both sides of the packaging paper; the blended coated layer comprises high temperature resistant polypropylene and polytetrafluoroethylene in a mass ratio of 1:(0.08-0.12).

[0006] Preferably, the packaging paper has a basis weight of 150–210 g / m². 2 Kraft paper.

[0007] By adopting the above technical solution, the coating layer in the coated paper of this application is a blend of polypropylene and polytetrafluoroethylene. Polytetrafluoroethylene, due to its special molecular structure, possesses excellent chemical stability and non-adhesive properties, and a very low coefficient of friction. As a component of the blended coating layer, it can effectively improve the barrier properties of the coated baking paper against moisture and oils, reduce the impact of packaging contents on the coated baking paper, and facilitate food storage.

[0008] Meanwhile, polytetrafluoroethylene (PTFE) has excellent high and low temperature resistance. It can maintain its stable performance and will not deform within a very wide temperature range, including -196 to 260°C. It has extremely high thermal stability and low temperature toughness.

[0009] Furthermore, since polypropylene is a non-polar compound with a non-polar long carbon chain structure, it can combine with polytetrafluoroethylene through induced coupling when blended, thereby improving the compatibility of the two and the dispersibility of polytetrafluoroethylene, and improving the performance and high temperature resistance of the resulting blended coating layer, meeting the needs of daily life for fresh bread-like foods that require low-temperature refrigeration and high-temperature heating.

[0010] Preferably, the blended coating layer comprises the following raw materials in parts by weight:

[0011] 100 parts of polypropylene;

[0012] 8-12 parts of polytetrafluoroethylene micro powder;

[0013] Catalyst A: 0-0.3 parts;

[0014] Antioxidant 0.4–0.6 parts;

[0015] Nucleating agent 0.6-0.8 parts.

[0016] Preferably, the particle size of the polytetrafluoroethylene micro powder is 20-50 μm.

[0017] Preferably, the nucleating agent is an α-nucleating agent, including one or a combination of sodium benzoate and sodium adipic acid.

[0018] Preferably, catalyst A comprises one or a combination of calcium carbonate, magnesium hydroxide, and zinc oxide.

[0019] Preferably, the antioxidant includes one or a combination of antioxidants BHT, BHA, and AT-10.

[0020] By adopting the above technical solution, this application introduces polytetrafluoroethylene (PTFE) into the blended coating layer by adding PTFE micropowder, thereby improving the high and low temperature resistance of the coated baking paper, reducing friction, and enhancing chemical stability. Furthermore, compared to directly adding PTFE resin, the smaller particle size of the PTFE micropowder allows for uniform dispersion in the high-temperature resistant polypropylene matrix, reducing potential agglomeration during processing and forming a finer dispersed phase. The micropowdered PTFE also exhibits better flowability, reducing processing difficulty. Simultaneously, the small particle size of the PTFE micropowder better maintains the transparency of the polypropylene, which is beneficial for the preparation of the coated baking paper.

[0021] Meanwhile, a nucleating agent is added to the raw materials of the blended coating layer. Polypropylene is a semi-crystalline polymer with poor temperature resistance. Adding a small amount of nucleating agent can increase the crystallinity of polypropylene, further improving its stability at high temperatures. The refinement of the crystalline structure can further increase the load deformation temperature of the blended coating layer, thereby improving the high and low temperature resistance of the coated baking paper. Furthermore, the addition of the nucleating agent also reduces the product molding cycle, which is beneficial for improving production efficiency.

[0022] Preferably, the polypropylene is high-temperature resistant polypropylene; the raw materials of the high-temperature resistant polypropylene include polypropylene and vinyl silane compound in a mass ratio of 1:(0.25-0.35).

[0023] By employing the above technical solution, the double bonds in vinyl silane compounds react with free radicals in polypropylene, allowing the vinyl silane compounds to be grafted onto the polypropylene molecular chain. This introduces siloxane segments into the polypropylene molecular chain, resulting in high-temperature resistant polypropylene. Furthermore, during the preparation of the blended coating layer, the alkoxy groups in the high-temperature resistant polypropylene molecular chain hydrolyze to release hydroxyl groups, forming silanols. These two silanol groups undergo dehydration condensation under the action of catalyst A to form siloxane bonds, thus creating crosslinks. This results in a final blended coating layer with a crosslinked network structure. This compact molecular structure not only enhances the mechanical strength of the blended coating layer but also significantly improves its temperature resistance.

[0024] Preferably, the vinyl silane compound is an amino-modified vinyl silane compound; the raw materials for the amino-modified vinyl silane compound include a vinyl silane compound and a polyamine compound in a mass ratio of 1:(0.1-0.2).

[0025] Preferably, the vinyl silane compound includes one or a combination of vinyltrimethoxysilane, vinyltriethoxysilane, and vinyltri(2-methoxyethoxy)silane; the polyamine compound includes one or a combination of ethylenediamine, hexamethylenediamine, and propylenediamine.

[0026] By adopting the above technical solution, the vinyl silane compound grafted onto the high-temperature resistant polypropylene molecular chain is also subjected to amino modification treatment. Since polypropylene and polytetrafluoroethylene are both non-polar polymers, their molecular chains do not have too many polar groups. Therefore, the bonding force between the blended coating layer and the packaging paper is limited. By first modifying the vinyl silane compound and then grafting it onto the polypropylene molecular chain, the introduced amino groups can form hydrogen bonds with the hydroxyl groups on the surface of the packaging paper during the coating process. This can improve the interfacial bonding force between the blended coating layer and the packaging paper, and greatly reduce the possible peeling, bubbling and other phenomena of the blended coating layer during use.

[0027] Preferably, the amino-modified vinylsilane compound is prepared according to the following method:

[0028] S1.1 Add vinyl silane compound and allyl methyl carbonate to solvent, mix well, adjust the solution temperature to 10-20℃, add alkaline catalyst, stir the reaction for 30-60 min, and after the reaction is completed, centrifuge and dry to obtain pretreated vinyl silane compound.

[0029] S1.2 Under a nitrogen atmosphere, a polyamine compound and catalyst B are added to the obtained pretreated vinylsilane compound, the temperature is raised to 40-50°C, and the reaction is stirred for 1-1.5 h to obtain a pre-reaction solution.

[0030] S1.3 The obtained pre-reaction solution was transferred to an aqueous ethanol solution, an acidic catalyst was added, the temperature was adjusted to 25-35℃, and after mixing for 30-40 min, the amino-modified vinyl silane compound was obtained by filtration and extraction.

[0031] Preferably, the solvent includes one or more of N,N-dimethylformamide and tetrahydrofuran.

[0032] Preferably, the alkaline catalyst includes one or a combination of sodium hydride, sodium ethoxide, and potassium tert-butoxide.

[0033] Preferably, catalyst B is one of tetraisopropyl titanate and potassium hydroxide.

[0034] Preferably, the acidic catalyst includes one or a combination of hydrochloric acid, sulfuric acid, and phosphoric acid.

[0035] By adopting the above technical solution, since the double bond is chemically active, it is first protected by allyl methyl carbonate before modification. Specifically, the carbonyl group in allyl methyl carbonate can attack the π bond of vinyl group to form a tetrahedral intermediate. Then, through proton transfer, a stable addition product is finally generated, which first converts the double bond in vinyl silane compound into a single bond structure, thus avoiding the participation of the double bond in subsequent reaction processes.

[0036] A portion of the alkoxy groups in the protected vinylsilane compound decomposes under the action of catalyst B to obtain silanol groups, which then further promote the reaction between the silanol groups and the amino groups in the polyamine compound, enabling the amino groups to be successfully modified onto the vinylsilane compound.

[0037] Finally, under the action of an acidic catalyst, water molecules can act as nucleophiles to attack the carbonyl carbon, initiating a ring-opening reaction, breaking the formed carbon-oxygen bond and simultaneously regenerating vinyl groups. After post-treatment to remove byproducts, amino-modified vinylsilane compounds are obtained.

[0038] Preferably, the high-temperature resistant polypropylene is prepared by the following method: adding a vinyl silane compound and an initiator to polypropylene after drying, mixing evenly, and then obtaining high-temperature resistant polypropylene by melt extrusion and cooling granulation.

[0039] Preferably, the initiator is one of benzoyl peroxide and azobisisobutyronitrile.

[0040] By adopting the above technical solution, during the melt extrusion process, polypropylene generates polymer free radicals during the thermal decomposition and hydrogen abstraction reaction of the initiator. These free radicals can react with the double bonds present in the vinyl silane compound, further enabling the vinyl silane compound to be successfully grafted onto the polypropylene molecular chain, thereby crosslinking during the blending and coating stage and improving the temperature resistance of polypropylene.

[0041] Secondly, this application also provides a manufacturing process for high and low temperature resistant coated baking paper, including the following process steps:

[0042] S2.1 The packaging paper is perforated, with a perforation diameter of 80-100 μm;

[0043] S2.2 High-temperature resistant polypropylene, polytetrafluoroethylene micro powder, catalyst A, antioxidant and nucleating agent are stirred and mixed, and then laminated with the packaging paper obtained in step S2.1 through a coating machine to obtain high and low temperature resistant coated baking paper, wherein the coating temperature is 325~335℃;

[0044] S2.3 The obtained high and low temperature resistant coated baking paper is wound and bagged by edge rolling.

[0045] By adopting the above technical solution, the packaging paper needs to be pretreated before lamination. Perforation can increase the actual contact area between the blended lamination layer and the packaging paper. The pores will form microscopic "anchor points" during the lamination process, which is conducive to improving the mechanical interlocking effect between the two. Under the condition that the raw materials of the blended lamination layer are non-polar polymers such as polypropylene and polytetrafluoroethylene, this pretreatment method is conducive to improving the adhesion between the blended lamination layer and the packaging paper, and will not easily delaminate or peel off due to environmental changes during use.

[0046] Preferably, in step S2.3, before the winding begins, a narrow-edged paper-plastic strip is placed inside the rolled edge of the high- and low-temperature resistant coated baking paper. One end of the narrow-edged paper-plastic strip is wound along with one end of the high- and low-temperature resistant coated baking paper, while the other end remains at the other end of the high- and low-temperature resistant coated baking paper for opening the packaging bag.

[0047] Preferably, the width of the narrow-edge paper-plastic strip is 1-2 cm; the weight of the narrow-edge paper-plastic strip is 190-230 g / m². 2 Kraft paper.

[0048] By adopting the above technical solution, a narrow paper-plastic strip is added to the inner side of the winding process of the high and low temperature resistant coated baking paper. The narrow paper-plastic strip is then wound along with the high and low temperature resistant coated baking paper, and the narrow paper-plastic strip left on the outside serves as a "pull rope" for unwinding, making it easy for people to open the finished packaging bag.

[0049] In summary, this application has the following beneficial effects:

[0050] 1. The high and low temperature resistant coated baking paper of this application includes a blended coating layer, which is a blend of high-temperature resistant polypropylene and polytetrafluoroethylene (PTFE). Both are non-polar polymers that can be bonded together through induced coupling, and both have good compatibility and dispersibility. PTFE has good chemical stability and non-adhesive properties, which can effectively improve the barrier properties of the coated baking paper against moisture and oils; furthermore, PTFE can maintain its performance stability over a very wide temperature range, exhibiting extremely high thermal stability and low-temperature toughness, giving the resulting blended coating layer excellent high and low temperature resistance.

[0051] 2. The high-temperature resistant polypropylene in the blended coating layer of this application has vinyl silane compounds grafted onto its molecular chains, which can initiate cross-linking reactions during the coating process to form a cross-linked network structure of polypropylene. This is beneficial to improving the load deformation temperature of polypropylene and improving its temperature resistance. Furthermore, the vinyl silane compounds have also undergone amino modification treatment, which is beneficial to improving the interfacial bonding force between the blended coating layer and the packaging paper.

[0052] 3. In the production process of coated baking paper, the packaging paper is first perforated to improve the mechanical locking force between the blended coating layer and the packaging paper, and to improve the bonding force between the two; and during the winding process of the high and low temperature resistant coated baking paper, a narrow paper-plastic strip is added inside, which is conducive to opening the finished packaging bag. Attached Figure Description

[0053] Figure 1 These are top and side views of the high and low temperature resistant coated baking paper before and after the winding process in Example 1.

[0054] Explanation of reference numerals in the attached figures:

[0055] 1. High and low temperature resistant coated baking paper; 2. Narrow edge paper-plastic strip. Detailed Implementation

[0056] Preparation examples of amino-modified vinylsilane compounds

[0057] Preparation Example 1-1: An amino-modified vinylsilane compound was prepared according to the following method:

[0058] 100g vinyltriethoxysilane and 70g allyl methyl carbonate were added to 250ml N,N-dimethylformamide. After mixing evenly, the solution temperature was adjusted to 10℃, 3g sodium hydride was added, and the mixture was stirred for 40min. After the reaction was completed, the pretreated vinyl silane compound was obtained by centrifugation and drying.

[0059] Under a nitrogen atmosphere, 100g of pretreated vinylsilane compound was taken and 15g of ethylenediamine and 0.5g of tetraisopropyl titanate were added. The temperature was raised to 50°C and the mixture was stirred for 1 hour to obtain a pre-reaction solution.

[0060] The obtained pre-reaction solution was transferred to 250 ml of 70% ethanol aqueous solution, 5 g of hydrochloric acid was added, the temperature was adjusted to 30 °C, and after mixing for 30 min, the amino-modified vinyl silane compound was obtained by filtration and extraction.

[0061] Preparation Example 1-2 is an amino-modified vinylsilane compound, which differs from Preparation Example 1-1 only in that the amount of ethylenediamine added is 10g.

[0062] Preparation Examples 1-3: An amino-modified vinylsilane compound, differing from Preparation Example 1-1 only in that the amount of ethylenediamine added is 20g.

[0063] Preparation Examples 1-4: An amino-modified vinylsilane compound, differing from Preparation Example 1-1 only in that the amount of ethylenediamine added is 5g.

[0064] Preparation Examples 1-5: An amino-modified vinylsilane compound, differing from Preparation Example 1-1 only in that the amount of ethylenediamine added is 25g.

[0065] Example of preparation of high temperature resistant polypropylene

[0066] Preparation Example 2-1: A high-temperature resistant polypropylene was prepared according to the following method:

[0067] 1000g of polypropylene (model R680F) was dried. Then, 300g of vinyltriethoxysilane and 5g of benzoyl peroxide were added to the dried polypropylene. After mixing evenly, the mixture was melt-extruded, cooled, and granulated to obtain high-temperature resistant polypropylene. The plasticizing temperature of the melt extrusion was 220℃.

[0068] Preparation Example 2-2, a high-temperature resistant polypropylene, differs from Preparation Example 2-1 only in that the amount of vinyltriethoxysilane added is 250g.

[0069] Preparation Example 2-3 is a high-temperature resistant polypropylene, which differs from Preparation Example 2-1 only in that the amount of vinyltriethoxysilane added is 350g.

[0070] Preparation Example 2-4 is a high-temperature resistant polypropylene, which differs from Preparation Example 2-1 only in that the amount of vinyltriethoxysilane added is 200g.

[0071] Preparation Example 2-5 is a high-temperature resistant polypropylene, which differs from Preparation Example 2-1 only in that the amount of vinyltriethoxysilane added is 400g.

[0072] Preparation Example 2-6, a high-temperature resistant polypropylene, differs from Preparation Example 2-1 only in that an equal amount of the amino-modified vinylsilane compound obtained in Preparation Example 1-1 is used instead of vinyltriethoxysilane.

[0073] Preparation Example 2-7, a high-temperature resistant polypropylene, differs from Preparation Example 2-1 only in that an equal amount of amino-modified vinylsilane compound obtained in Preparation Example 1-2 is used instead of vinyltriethoxysilane.

[0074] Preparation Examples 2-8, a high-temperature resistant polypropylene, differs from Preparation Example 2-1 only in that an equal amount of the amino-modified vinylsilane compound obtained in Preparation Examples 1-3 is used instead of vinyltriethoxysilane.

[0075] Preparation Examples 2-9, a high-temperature resistant polypropylene, differs from Preparation Example 2-1 only in that an equal amount of the amino-modified vinylsilane compound obtained in Preparation Examples 1-4 is used instead of vinyltriethoxysilane.

[0076] Preparation Example 2-10, a high-temperature resistant polypropylene, differs from Preparation Example 2-1 only in that an equal amount of the amino-modified vinylsilane compound obtained in Preparation Example 1-5 is used instead of vinyltriethoxysilane.

[0077] Example

[0078] Example 1: A high and low temperature resistant coated baking paper is prepared according to the following process steps:

[0079] S2.1 The packaging paper (with an average weight of 180g / m²) 2 The kraft paper is perforated with a hole diameter of 80μm.

[0080] S2.2 1000g of polypropylene (model R680F), polytetrafluoroethylene micro powder (average particle size of 30μm), 5g of antioxidant AT-10 and 7g of sodium benzoate are stirred and mixed, and then laminated with the packaging paper obtained in step S2.1 through a laminating machine to obtain a double-sided laminated baking paper resistant to high and low temperatures, wherein the laminating temperature is 330℃;

[0081] S2.3 The obtained high and low temperature resistant coated baking paper is wound. Before winding begins, a narrow strip of paper-plastic material (with an average weight of 200g / m²) is placed on the inside of the rolled edge of the high and low temperature resistant coated baking paper. 2The kraft paper (1cm wide) is used to make the bag by rolling the edges of one end along with the high and low temperature resistant baking paper, while the other end is left on the other end of the high and low temperature resistant baking paper for opening the packaging bag.

[0082] Examples 2 to 5 describe a high- and low-temperature resistant coated baking paper, differing from Example 1 only in the raw material ratio of the blended coating layer, as shown in Table 1.

[0083] Table 1. Formulation of the co-coated membrane layer in Examples 1 to 5

[0084] Example 1 Example 2 Example 3 Example 4 Example 5 polypropylene 1000 1000 1000 1000 1000 polytetrafluoroethylene micro powder 100 80 120 100 100 Antioxidant AT-10 5 5 5 4 6 Sodium benzoate 7 7 7 6 8

[0085] Example 6, a high and low temperature resistant coated baking paper, differs from Example 1 only in that step S2.2 is performed according to the following method:

[0086] 1000g of polypropylene (model R680F) prepared in Preparation Example 2-1, polytetrafluoroethylene micro powder (average particle size of 30μm), 2g of calcium carbonate, 5g of antioxidant AT-10 and 7g of sodium benzoate were stirred and mixed, and then laminated with the packaging paper obtained in step S2.1 through a laminating machine to obtain a double-sided laminated baking paper resistant to high and low temperatures, wherein the laminating temperature is 330℃.

[0087] Example 7 is a high and low temperature resistant coated baking paper, which differs from Example 6 only in that the high temperature resistant polypropylene prepared in Preparation Example 2-1 is replaced with an equal amount of the high temperature resistant polypropylene prepared in Preparation Example 2-2.

[0088] Example 8 is a high and low temperature resistant coated baking paper, which differs from Example 6 only in that the high temperature resistant polypropylene prepared in Preparation Example 2-1 is replaced with an equal amount of the high temperature resistant polypropylene prepared in Preparation Example 2-3.

[0089] Example 9, a high and low temperature resistant coated baking paper, differs from Example 6 only in that the high temperature resistant polypropylene prepared in Example 2-1 is replaced with an equal amount of the high temperature resistant polypropylene prepared in Example 2-4.

[0090] Example 10, a high and low temperature resistant coated baking paper, differs from Example 6 only in that the high temperature resistant polypropylene prepared in Preparation Example 2-1 is replaced with an equal amount of the high temperature resistant polypropylene prepared in Preparation Example 2-5.

[0091] Example 11, a high and low temperature resistant coated baking paper, differs from Example 6 only in that the high temperature resistant polypropylene prepared in Preparation Example 2-1 is replaced with an equal amount of the high temperature resistant polypropylene prepared in Preparation Example 2-6.

[0092] Example 12, a high and low temperature resistant coated baking paper, differs from Example 6 only in that the high temperature resistant polypropylene prepared in Preparation Example 2-1 is replaced with an equal amount of the high temperature resistant polypropylene prepared in Preparation Example 2-7.

[0093] Example 13, a high and low temperature resistant coated baking paper, differs from Example 6 only in that the high temperature resistant polypropylene prepared in Preparation Example 2-1 is replaced with an equal amount of the high temperature resistant polypropylene prepared in Preparation Example 2-8.

[0094] Example 14, a high and low temperature resistant coated baking paper, differs from Example 6 only in that the high temperature resistant polypropylene prepared in Example 2-1 is replaced with an equal amount of the high temperature resistant polypropylene prepared in Example 2-9.

[0095] Example 15, a high and low temperature resistant coated baking paper, differs from Example 6 only in that the high temperature resistant polypropylene prepared in Preparation Example 2-1 is replaced with an equal amount of the high temperature resistant polypropylene prepared in Preparation Example 2-10.

[0096] Example 16: A high and low temperature resistant coated baking paper, which differs from Example 1 only in that, in step S2.2, a single-sided coated high and low temperature resistant coated baking paper is obtained through coating.

[0097] Example 17, a high and low temperature resistant coated baking paper, differs from Example 1 only in that sodium benzoate is not added.

[0098] Example 18, a high and low temperature resistant coated baking paper, differs from Example 1 only in that polytetrafluoroethylene micro powder with an average particle size of 30 μm is replaced with polytetrafluoroethylene micro powder with an average particle size of 500 μm.

[0099] Comparative Example

[0100] Comparative Example 1 is a high and low temperature resistant coated baking paper, which differs from Example 1 only in that the amount of polytetrafluoroethylene micro powder added is 70g.

[0101] Comparative Example 2, a high and low temperature resistant coated baking paper, differs from Example 1 only in that the amount of polytetrafluoroethylene micro powder added is 130g.

[0102] Comparative Example 3 is a high and low temperature resistant coated baking paper, which differs from Example 1 only in that the packaging paper is not perforated.

[0103] Comparative Example 4 is a high and low temperature resistant coated baking paper, which differs from Example 1 only in that it does not contain polytetrafluoroethylene micro powder.

[0104] Performance testing

[0105] 1. Peel strength test: The peel strength of the obtained high and low temperature resistant coated baking paper was tested according to the relevant records in GB / T 8808-88 "Peel test method for flexible composite plastic materials".

[0106] 2. Mechanical strength test: According to the relevant records in GB / T 1130-91 "Test method for right angle tear performance of plastics", the right angle tear strength of the obtained high and low temperature resistant coated baking paper is tested to characterize the mechanical strength of the material.

[0107] 3. High and low temperature resistance test:

[0108] (1) High temperature resistance test: The obtained high and low temperature resistant coated baking paper was placed in a high temperature environment, and the temperature at which the sample surface began to soften was recorded as the heat-resistant melting temperature.

[0109] (2) Low temperature resistance test: The obtained high and low temperature resistant coated baking paper was stored at -10℃ for 12h. According to the relevant records in GB / T1130-91 "Test method for right angle tear performance of plastic", the right angle tear strength of the high and low temperature resistant coated baking paper after low temperature treatment was tested.

[0110] The experimental results are shown in Table 2.

[0111] Table 2 Performance Test Results of High and Low Temperature Resistant Coated Baking Paper

[0112]

[0113] Combining Examples 1 and 2 through 5, it can be seen that there are no significant differences in peel strength, right-angle tear strength before and after low-temperature treatment, and heat-resistant melting temperature between Examples 2 through 5 and Example 1. This indicates that the bonding force, high and low temperature resistance, and mechanical strength between the blended coating layer and the packaging paper in Examples 2 through 5 are not significantly different from those in Example 1. This may be because the only difference between Examples 2 through 5 and Example 1 is that the raw material ratio of the blended coating layer in Examples 2 through 5 was adjusted within the required range, which has no significant impact on the performance of the final coated baking paper and fluctuates within an acceptable range.

[0114] Combining Examples 1 and 6-8, it can be seen that Example 6 shows a significant improvement in right-angle tear strength and heat-resistance temperature before and after low-temperature treatment compared to Example 1. This indicates that Example 6 exhibits significantly improved high and low temperature resistance and mechanical strength compared to Example 1. Examples 7 and 8 show no significant difference in performance compared to Example 6. This may be because the polypropylene used in Example 6 is high-temperature resistant polypropylene with vinyl silane compounds grafted onto its molecular chains. These compounds can react and crosslink during the formation of the blended coating layer, improving the overall temperature resistance and mechanical properties. Examples 7 and 8, compared to Example 6, only varied the amount of vinyl silane compounds grafted within a certain range, having little impact on the material.

[0115] Based on Examples 6, 9, and 10, it can be seen that the right-angle tear strength and heat-resistant melting temperature of Examples 9 and 10 decreased compared to Example 6 before and after low-temperature treatment. This indicates that the high and low temperature resistance and mechanical strength of Examples 9 and 10 decreased compared to Example 6. The reason for this may be that Examples 9 and 10 reduced or increased the amount of vinyl silane compound added during the preparation of high-temperature resistant polypropylene. Reducing the amount added leads to insufficient crosslinking, limiting the improvement of temperature resistance; increasing the amount added easily causes self-crosslinking, which is not conducive to improving temperature resistance and mechanical properties.

[0116] Combining Examples 6 and 11-13, it can be seen that the peel strength of Example 11 is improved compared to Example 6, indicating that the adhesion between the blended coating layer and the packaging paper is increased in Example 11 compared to Example 6. The performance of Examples 12 and 13 is not significantly different from that of Example 11. This may be because, compared to Example 6, the vinyl silane compound grafted onto polypropylene in Example 11 underwent amino modification treatment, resulting in a blended coating layer containing amino groups that can interact with the polar groups on the surface of the packaging paper, thus improving the adhesion between the coating layer and the packaging paper during the coating process. Examples 12 and 13, compared to Example 11, only varied the amount of polyamine compound used in the amino modification process within the required range, having little impact on the performance of the resulting baking paper.

[0117] Based on Examples 11, 14, and 15, it can be seen that the peel strength of Examples 14 and 15 is lower than that of Example 11. This indicates that the adhesion between the blended coating layer and the packaging paper in Examples 14 and 15 is lower than that in Example 11. The reason for this may be that the amount of polyamine compound added in the amino-modified vinyl silane compound used in Examples 14 and 15 was reduced or increased during the preparation process. Reducing the amount of polyamine compound added significantly reduces the number of polar groups, resulting in a decrease in adhesion. Increasing the amount of polyamine compound added limits the number of active sites. Not all polyamine compounds can be modified on the molecular chain of the vinyl silane compound, and the competition may lead to a decrease in the content of polar groups.

[0118] Combining Examples 1 and 16, it can be seen that the right-angle tear strength of Example 16 at room temperature is lower than that of Example 1. The reason may be that Example 16 is a single-sided coated baking paper, with only one side having a blended coating layer, which significantly reduces the improvement in mechanical properties compared to Example 1.

[0119] Combining Examples 1 and 17, it can be seen that the right-angle tear strength and heat-resistance melting temperature of Example 17 are lower than those of Example 1 before and after low-temperature treatment, indicating that the mechanical strength and high and low temperature resistance of Example 17 are reduced. This may be because no nucleating agent was added to the blended coating layer in Example 17, resulting in a decrease in the crystallization ability of polypropylene, which reduces the temperature resistance of the polypropylene base material. Furthermore, the decrease in crystallinity also leads to a decrease in the strength of the formed coating layer.

[0120] Combining Examples 1 and 18, it can be seen that the peel strength, right-angle tear strength before and after low-temperature treatment, and heat-resistance temperature of Example 18 are all lower than those of Example 1. This may be because Example 18 uses large-particle-size polytetrafluoroethylene (PTFE) micropowder. Increasing the particle size makes PTFE micropowder less dispersed. As a non-polar polymer with a very low coefficient of friction, its bonding force with the packaging paper decreases, and uneven dispersion also leads to a reduction in the material's resistance to high and low temperatures.

[0121] Based on Examples 1, 2, and 4, it can be seen that the peel strength, right-angle tear strength before and after low-temperature treatment, and heat-resistance temperature of Examples 1, 2, and 4 are all lower than those of Example 1, with Comparative Example 4 showing the most significant decrease in high and low temperature resistance. This may be because the amount of polytetrafluoroethylene (PTFE) powder added in Comparative Examples 1, 2, and 4 was adjusted outside the normal range during the preparation of the blended coating layer. In Comparative Example 1, the reduced PTFE content resulted in a slight decrease in the improvement of high and low temperature resistance, while Comparative Example 4, which did not add PTFE, showed a more significant performance decrease. In Comparative Example 2, the increased PTFE content, on the one hand, leads to a significant decrease in the bonding force between PTFE and the packaging paper due to its non-polar nature; on the other hand, the increased content affects the dispersion of PTFE in polypropylene, resulting in a decrease in performance.

[0122] Combining Example 1 and Comparative Example 3, it can be seen that the peel strength, right-angle tear strength before and after low-temperature treatment, and heat-resistant melting temperature of Comparative Example 3 are all lower than those of Example 1. This may be because Comparative Example 3 did not perform a pre-treatment of perforating the packaging paper. Since polypropylene and polytetrafluoroethylene are both non-polar polymers, their molecular chains do not have excess polar groups that can bond with the groups on the surface of the packaging paper. Perforation treatment can improve the mechanical bonding force between the blended coating layer and the packaging paper, thereby increasing the adhesion between them.

[0123] This specific embodiment is merely an explanation of this application and is not intended to limit it. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but such modifications are protected by patent law as long as they fall within the scope of the claims of this application.

Claims

1. A high and low temperature resistant laminated baking paper comprising a blended laminated layer and a wrapping paper, characterized in that, The blended coating film layer is on one side or both sides of the packaging paper; the blended coating film layer comprises polypropylene and polytetrafluoroethylene in a mass ratio of 1: (0.08-0.12) ; The blended coating film layer comprises the following raw materials in the following mass fractions: Polypropylene 100 parts; Polytetrafluoroethylene micro powder 8-12 parts; Catalyst A 0-0.3 parts; Antioxidant 0.4-0.6 parts; Nucleating agent 0.6-0.8 parts; The polypropylene is high-temperature-resistant polypropylene; the raw materials of the high-temperature-resistant polypropylene comprise polypropylene and a vinyl silane compound in a mass ratio of 1: (0.25-0.35) ; The vinyl silane compound is an amino-modified vinyl silane compound; the raw materials of the amino-modified vinyl silane compound comprise a vinyl silane compound and a polyamine compound in a mass ratio of 1: (0.1-0.2).

2. The high and low temperature resistant coating baking paper according to claim 1, characterized in that, The vinyl silane compound comprises one or a combination of several of vinyl trimethoxysilane, vinyl triethoxysilane, and vinyl tris (2-methoxyethoxy) silane; the polyamine compound comprises one or a combination of several of ethylenediamine, hexanediamine, and propylenediamine.

3. The high and low temperature resistant coating baking paper according to claim 1, characterized in that, The amino-modified vinyl silane compound is prepared by the following method: S1.1 adding a vinyl silane compound and allyl methyl carbonate in a solvent, uniformly mixing, adjusting the solution temperature to 10-20℃, adding an alkaline catalyst, stirring for 30-60 min, and obtaining a pretreated vinyl silane compound after centrifugal separation and drying; S1.2 adding a polyamine compound and a catalyst B to the obtained pretreated vinyl silane compound under a nitrogen atmosphere, increasing the temperature to 40-50℃, stirring for 1-1.5 h, and obtaining a pre-reaction solution; S1.3 transferring the obtained pre-reaction solution into an ethanol aqueous solution, adding an acidic catalyst, adjusting the temperature to 25-35℃, mixing for 30-40 min, and obtaining an amino-modified vinyl silane compound after filtration and extraction.

4. The high and low temperature resistant coating baking paper according to claim 1, characterized in that, The high-temperature-resistant polypropylene is prepared by the following method: adding a vinyl silane compound and an initiator to the polypropylene after drying treatment, uniformly mixing, and obtaining the high-temperature-resistant polypropylene by melt extrusion and cooling granulation.

5. The high and low temperature resistant coating baking paper according to claim 1, characterized in that, The particle size of the polytetrafluoroethylene micro powder is 20-50 μm.

6. The process for the production of high and low temperature resistant coated baking paper according to any one of claims 1 to 5, characterized in that, The method comprises the following steps: S2.1 perforating the packaging paper, with a perforation diameter of 80-100 μm; S2.2 mixing the high-temperature-resistant polypropylene, the polytetrafluoroethylene micro powder, the catalyst A, the antioxidant, and the nucleating agent, and then compounding the mixture with the packaging paper obtained in S2.1 by a coating machine to obtain a high-temperature-resistant coating baking paper, wherein the coating temperature is 325-335℃; S2.3 winding the obtained high-temperature-resistant coating baking paper, and making bags by edge rolling.

7. The process for the production of high and low temperature resistant coated baking paper according to claim 6, characterized in that, In the step S2.3, a narrow plastic strip is placed inside the edge of the high-temperature-resistant coating baking paper before winding, one end of the narrow plastic strip is wound with one end of the high-temperature-resistant coating baking paper, and the other end is reserved at the other end of the high-temperature-resistant coating baking paper for opening the packaging bag.

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