Modified solvent type ink for brushing PVC (Polyvinyl Chloride) mask and preparation method of modified solvent type ink

Abstract

The invention discloses modified solvent type ink for brushing a PVC (polyvinyl chloride) mask and a preparation method of the modified solvent type ink, belongs to the technical field of polymer ink production, and aims to solve the problems of after-tack shedding caused by migration of a plasticizer during brushing of a soft PVC mask, ink layer embrittlement caused by traditional anti-sticking, poor stain resistance, water whitening resistance and the like. The invention provides modified solvent type ink and a preparation method thereof. The ink is prepared from vinyl chloride-vinyl acetate resin matrix resin liquid, a dual-modified synergistic prepolymer, pigment, an anti-settling agent, a dispersing agent and a mixed solvent, the prepolymer is prepared by reacting dimer alcohol with hydroxyl-terminated PDMS (polydimethylsiloxane) and IPDI (isophorone diisocyanate) and carrying out MEKO end capping. Through a gradient structure of an internal soft segment compatible buffer plasticizer and a surface silicon segment low surface energy barrier, high anti-adhesion and high stain resistance are realized, and flexibility, adhesive force and recoatability are maintained at the same time.

Description

Technical Field

[0001] This invention belongs to the field of polymer ink production technology, specifically relating to a modified solvent-based ink for coating PVC face films and its preparation method. Background Technology

[0002] Flexible polyvinyl chloride (PVC) is widely used in the production of products such as special effects face masks, mannequin heads, and inflatable dolls due to its soft touch and high degree of realism. To give these products realistic skin tones and textures, ink coating is applied to their surface.

[0003] However, existing solvent-based PVC inks (usually based on chloroacetic acid resin systems) suffer from the following serious technical drawbacks in practical applications: (1) Re-adhesion and shedding caused by plasticizer migration: Flexible PVC contains up to 30% to 50% plasticizers (such as DOP and DINP). Under high temperature or long-term storage, plasticizers will migrate to the ink layer, causing the ink resin to swell and become sticky (poor anti-blocking performance), and in severe cases, stacked products will stick together and become unusable.

[0004] (2) Contradictions in mechanical properties: To prevent sticking, the traditional approach is to increase the hardness of the resin (such as increasing the proportion of vinyl chloride) or add a large amount of wax powder. However, this will cause the ink layer to become brittle, and cracks will appear in the ink layer when the film is bent or stretched at a large angle; while adding too much wax powder will result in poor recoatability and reduced gloss.

[0005] In addition, there is a pain point in existing technologies that is often overlooked but objectively exists: (3) Poor stain resistance and water whitening resistance: PVC masks come into contact with human sweat, oil, and even cosmetics during wear. Traditional chloroacetic acid inks have a relatively loose microstructure and strong oleophilicity. Once they are stained with foundation, lipstick, or oil-based markers, the stains easily penetrate into the ink layer and cannot be wiped off (i.e., the "color absorption" phenomenon). At the same time, in humid environments, water molecules seep into the ink layer, causing a "whitening" phenomenon, which affects the appearance.

[0006] Currently available single modification methods (such as grafting long-chain fatty acids or adding only silicone additives) cannot solve all the above problems at the same time. While using long-chain fatty acids alone improves flexibility, it results in insufficient surface dryness and stain resistance; while adding silicone leveling agents alone improves the feel, it easily leads to loss of interlayer adhesion (making recoating difficult) and cannot prevent plasticizers from eroding the substrate.

[0007] Therefore, developing a smart ink that can both absorb plasticizers internally to maintain flexibility and construct a super-amphiphobic (hydrophobic and oleophobic) barrier externally to resist staining and prevent sticking is a problem that urgently needs to be solved in this field. Summary of the Invention

[0008] The purpose of this invention is to provide a modified solvent-based ink for PVC face mask coating and its preparation method. This invention designs a special "dual soft segment block copolymer end-capping curing agent" and utilizes the synergistic assembly of dimer glycol and hydroxyl-terminated polydimethylsiloxane (PDMS-OH) on the molecular chain to achieve a "gradient distribution" of ink coating performance, thereby simultaneously solving the problems of tackiness, brittleness and poor stain resistance.

[0009] To achieve the above objectives, the present invention adopts the following technical solution.

[0010] A modified solvent-based ink for coating PVC face masks comprises the following raw materials in parts by weight: 45-55 parts of main resin solution; 12–18 parts of the dual-modified synergistic prepolymer; 20-30 parts pigment; Anti-settling agent 0.2-0.5 parts; Dispersant 0.5–2.0 parts; Mixed solvent 10-20 parts.

[0011] The main resin solution is a binary chloroacetic acid resin-ethyl acetate solution with a solid content of 30%.

[0012] The pigment in question is titanium dioxide.

[0013] The anti-settling agent is organic bentonite or fumed silica.

[0014] The dispersant is either BYK-163 or BYK-110.

[0015] The mixed solvent is prepared by mixing butanone and butyl acetate in a volume ratio of 6:4.

[0016] The dual-modified synergistic prepolymer is prepared by the following steps: Step A1: Mix the dimerol and hydroxyl-terminated polydimethylsiloxane, and dehydrate them at 105-110℃ and -0.098MPa vacuum for 1.5-2.0h to obtain the mixture; Design principle: Strictly control the ratio of dimer acid to silicone. Dimer acid, as the "bulk soft segment," provides aliphatic long chains similar to PVC plasticizers, giving the ink layer excellent flexibility and compatibility buffering ability against plasticizers; silicone, as the "surface functional segment," utilizes its extremely low surface energy to migrate to the surface during film formation, providing stain resistance and a smooth feel.

[0017] Step A2: Cool the mixture to 55-60℃, add isophorone diisocyanate to it, and then add bismuth neodecanoate to the system. Heat the system to 80-85℃ and react for 3-5 hours. After the reaction is complete, the copolymer is obtained. Reaction process: At this stage, IPDI reacts with dimer glycol and organosilane alcohol respectively to generate block prepolymer chains with -NCO groups at both ends. Due to the difference in reactivity between the two and the control of the feeding sequence, a polyurethane backbone containing siloxane segments and long-chain alkyl segments is formed.

[0018] Step A3: Cool the copolymer to 45-50°C, add methyl ethyl ketone oxime dropwise, and then maintain the temperature for the reaction until the infrared spectrum reaches 2270 cm⁻¹. -1 The -NCO characteristic peak disappears at the point, yielding the product; Step A4: Add ethyl acetate to the product to adjust the solid content to 50%–60%. After completion, the dual-modified synergistic prepolymer is obtained.

[0019] The ratio of the amounts of dimerol, hydroxyl-terminated polydimethylsiloxane, isophorone diisocyanate, bismuth neodecanoate, and methyl ethyl ketone oxime is 80g:20g:50-55g:4-5g:22-25g.

[0020] The preparation method of the modified solvent-based ink for coating PVC face films includes the following steps: Step S1: Weigh each raw material according to the weight parts, mix and stir 40% of the total amount of main resin liquid, dispersant and pigment for 15-30 minutes to obtain color paste; Step S2: Add the dual-modified synergistic prepolymer to the remaining main resin solution at a stirring speed of 800-1000 rpm, and mix for 15-30 min to obtain the mixed components; Step S3: Add the color paste, anti-settling agent and mixed solvent prepared in step S1 to the mixed components, mix and stir for 5-10 minutes to obtain the crude product; Step S4: After grinding the coarse product, filter it through a 300-mesh filter to obtain the finished modified solvent-based ink for PVC film coating.

[0021] Compared with the prior art, the present invention has at least the following beneficial effects: This invention proposes to synergistically construct a "dual-modified synergistic prepolymer" using "dimer glycol soft segments + PDMS-OH surface functional segments" and introduce it into the ink system. This allows for internal compatibility buffering of the plasticizer and the formation of a low surface energy barrier from the outside, achieving a "gradient distribution" of coating performance. The beneficial effects can be directly confirmed by combining Examples 4-6, Comparative Examples 2-3, and the data in Table 1. (1) Significantly improved anti-blocking properties. Table 1 shows that Example 4 was grade 4, while Examples 5 and 6 were both grade 5. However, Comparative Example 3, which removed the prepolymer under the same main resin liquid, pigment, additives, and process conditions, was only grade 1, indicating that the introduction of the "dual-modified synergistic prepolymer" played a decisive role in suppressing high-temperature stacking adhesion. Furthermore, Example 5 and Comparative Example 2 differed only in the "prepolymer type" (Example 5 was a dual-modified synergistic prepolymer containing PDMS-OH; Comparative Example 2 was a prepolymer in which PDMS-OH was replaced by dimerol), and its anti-blocking score dropped from grade 5 to grade 3. This proves that the improvement in anti-blocking properties is not solely due to the addition of a certain polyurethane prepolymer, but is directly related to the synergistic structure constructed by the PDMS segment.

[0022] (2) Significantly improved stain resistance (resistance to stain absorption). Table 1 shows that Example 4 is grade 4, Examples 5 and 6 are grade 5, and Comparative Example 3 is grade 1, indicating that without this prepolymer, lipstick / oil pen stains are more likely to remain or penetrate and are difficult to wipe off. Furthermore, Example 5 decreased from grade 5 to grade 2 compared to Comparative Example 2, which also points to the fact that the dual-modified synergistic structure formed by PDMS-OH is the key contributor to achieving high stain resistance (low penetration / easy wiping), which cannot be achieved by ordinary soft segment prepolymers.

[0023] (3) While improving anti-sticking and stain resistance, flexibility, adhesion, and recoatability are maintained. Table 1 shows that Examples 4-6 all passed the 180° folding test (50 times) and the recoatability of the second coat was also "passed". This indicates that the present invention achieves high anti-sticking and high stain resistance without sacrificing bending performance or interlayer adhesion. The fact that Comparative Example 3 failed the bending test proves that when the prepolymer is lacking in this system, the ink layer is more prone to cracking or peeling under large and repeated deformation. On the other hand, Comparative Example 2 still passed the bending test and recoatability test, but its anti-sticking and stain resistance were significantly worse, further proving that the advantages of the present invention are concentrated in the two key pain points of "anti-sticking + stain resistance", and this advantage is not an illusion caused by the difference in recoatability (because the recoatability was "passed" in both Example 5 and Comparative Example 2). Detailed Implementation

[0024] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0025] Example 1 Preparation of dual-modified synergistic prepolymers: Step A1: Raw material dehydration: 80g of dimer alcohol (Pripol 2033, Croda, dimer content ≥96%) and 20g of hydroxyl-terminated polydimethylsiloxane (PDMS-OH, IOTA 201 series double-hydroxyl-terminated silicone oil, Anhui Aiyota Silicone Oil Co., Ltd., molecular weight 1800) were mixed and dehydrated at 105℃ and -0.098MPa vacuum for 1.5h to obtain the mixture; Step A2: Block copolymerization (synergistic grafting): The mixture is cooled to 55°C, and 50g of isophorone diisocyanate (IPDI, Wanhua Chemical) is added to it. After that, 4g of organic bismuth catalyst bismuth neodecanoate (Coscat 83, bismuth metal content (Bi%) 20.0±0.5%, Vertellus, USA) is added to the system. The system is heated to 80°C and reacted for 3 hours. After that, the copolymer is obtained. Step A3: End-capping protection: Cool the copolymer to 45°C, and add 22g of the end-capping agent methyl ethyl ketone oxime (MEKO, domestic industrial grade) dropwise. After completion, maintain the temperature for the reaction until the infrared spectrum reaches 2270cm. -1 The -NCO characteristic peak disappears at the point, yielding the product; Step A4: Dilution: Add ethyl acetate to the product to adjust the solid content to 50%. After this is done, the dual-modified synergistic prepolymer is obtained.

[0026] Example 2 Preparation of dual-modified synergistic prepolymers: Step A1: Raw material dehydration: 80g of dimer alcohol (Pripol 2033, Croda, dimer content ≥96%) and 20g of hydroxyl-terminated polydimethylsiloxane (PDMS-OH, IOTA 201 series double-hydroxyl-terminated silicone oil, Anhui Aiyota Silicone Oil Co., Ltd., molecular weight 1800) were mixed and dehydrated at 105℃ and -0.098MPa vacuum for 2.0h to obtain the mixture; Step A2: Block copolymerization (synergistic grafting): The mixture is cooled to 55°C, and 54g of isophorone diisocyanate (IPDI, Wanhua Chemical) is added to it. After that, 5g of organic bismuth catalyst bismuth neodecanoate (Coscat 83, bismuth metal content (Bi%) 20.0±0.5%, Vertellus, USA) is added to the system. The system is heated to 80°C and reacted for 4 hours. After that, the copolymer is obtained. Step A3: End-capping protection: Cool the copolymer to 50°C, and add 24g of the end-capping agent methyl ethyl ketone oxime (MEKO, domestic industrial grade) dropwise. After completion, maintain the temperature for the reaction until the infrared spectrum reaches 2270cm. -1 The -NCO characteristic peak disappears at the point, yielding the product; Step A4: Dilution: Add ethyl acetate to the product to adjust the solid content to 55%. After this step, the dual-modified synergistic prepolymer is obtained.

[0027] Example 3 Preparation of dual-modified synergistic prepolymers: Step A1: Raw material dehydration: 80g of dimer alcohol (Pripol 2033, Croda, dimer content ≥96%) and 20g of hydroxyl-terminated polydimethylsiloxane (PDMS-OH, IOTA 201 series double-hydroxyl-terminated silicone oil, Anhui Aiyota Silicone Oil Co., Ltd., molecular weight 1800) were mixed and dehydrated at 110℃ and -0.098MPa vacuum for 2.0h to obtain the mixture; Step A2: Block copolymerization (synergistic grafting): The mixture is cooled to 60°C, and 55g of isophorone diisocyanate (IPDI, Wanhua Chemical) is added to it. After that, 5g of organic bismuth catalyst bismuth neodecanoate (Coscat 83, bismuth metal content (Bi%) 20.0±0.5%, Vertellus, USA) is added to the system. The system is heated to 85°C and reacted for 5 hours. After that, the copolymer is obtained. Step A3: End-capping protection: Cool the copolymer to 50°C, and add 25g of the end-capping agent methyl ethyl ketone oxime (MEKO, domestic industrial grade) dropwise. After completion, maintain the temperature for the reaction until the infrared spectrum reaches 2270cm. -1 The -NCO characteristic peak disappears at the point, yielding the product; Step A4: Dilution: Add ethyl acetate to the product to adjust the solid content to 60%. After completion, the dual-modified synergistic prepolymer is obtained.

[0028] Comparative Example 1 Comparative Example 1 served as the control group for Example 2. The hydroxyl-terminated polydimethylsiloxane in step A1 of Example 2 was replaced with an equal mass of dimer alcohol (Pripol 2033, Croda, dimer content ≥96%). The dehydration process remained unchanged, and a dehydrated material was obtained. The mixture in step A2 of Example 2 was replaced with the dehydrated material. The remaining raw materials, raw material amounts, and preparation steps remained consistent with those in Example 2, and a prepolymer was finally obtained.

[0029] Example 4 A modified solvent-based ink for coating PVC face masks and its preparation method: First, the modified solvent-based ink for coating PVC face masks comprises the following raw materials in parts by weight: 45 parts of the main resin solution (30% solid content binary chloroacetic acid resin-ethyl acetate solution); 12 portions of the dual-modified synergistic prepolymer prepared in Example 1; 20 parts of pigment titanium dioxide (R-996, Longbai Group); Anti-settling agent: 0.2 parts of organic bentonite (Bentone SD-1, Elementis); 0.5 parts of dispersant BYK-163 (BYK, Germany); 10 parts of mixed solvent (prepared by mixing butanone and butyl acetate in a volume ratio of 6:4).

[0030] Then, the method for preparing modified solvent-based inks for coating PVC masks includes the following steps: Step S1: Preparation of color paste: Weigh each raw material according to the weight parts, mix and stir 40% of the total amount of the main resin liquid (30% solid content of binary chloroacetic acid resin-ethyl acetate solution), dispersant BYK-163 (Germany BYK), and pigment titanium dioxide (R-996, Longbai Group) for 15 minutes to obtain color paste; Step S2: High-speed dispersion: Add the dual-modified synergistic prepolymer prepared in Example 1 to the remaining main resin liquid at a stirring speed of 800 rpm, mix and stir for 15 min to obtain a mixed component; Step S3: Paint mixing: Add the color paste prepared in step S1, the anti-settling agent organic bentonite (Bentone SD-1, Elementis) and the mixed solvent (butanone and butyl acetate prepared in a volume ratio of 6:4) to the mixed components, mix and stir for 5 minutes to obtain the crude product; Step S4: Filtration and Packaging: After grinding the coarse product, it is filtered through a 300-mesh filter to obtain the finished modified solvent-based ink for PVC film coating.

[0031] Example 5 A modified solvent-based ink for coating PVC face masks and its preparation method: First, the modified solvent-based ink for coating PVC face masks comprises the following raw materials in parts by weight: 50 parts of the main resin solution (30% solid content binary chloroacetic acid resin-ethyl acetate solution); 15 parts of the dual-modified synergistic prepolymer prepared in Example 2; 25 parts of pigment titanium dioxide (R-996, Longbai Group); Anti-settling agent: 0.5 parts of fumed silica (Aerosil 200, Evonik); Dispersant BYK-110 (BYK, Germany) 2.0 parts; 15 parts of mixed solvent (prepared by mixing butanone and butyl acetate in a volume ratio of 6:4).

[0032] Then, the method for preparing modified solvent-based inks for coating PVC masks includes the following steps: Step S1: Preparation of color paste: Weigh each raw material according to the weight parts, mix and stir 40% of the total amount of the main resin liquid (30% solid content of binary chloroacetic acid resin-ethyl acetate solution), dispersant BYK-110 (Germany BYK), and pigment titanium dioxide (R-996, Longbai Group) for 30 minutes to obtain color paste; Step S2: High-speed dispersion: At a stirring speed of 1000 rpm, the dual-modified synergistic prepolymer prepared in Example 2 was added to the remaining main resin liquid, and the mixture was stirred for 30 min to obtain the mixed components; Step S3: Paint mixing: Add the color paste prepared in step S1, the anti-settling fumed silica (Aerosil 200, Evonik), and the mixed solvent (butanone and butyl acetate prepared in a volume ratio of 6:4) to the mixed components, mix and stir for 10 minutes to obtain the crude product; Step S4: Filtration and Packaging: After grinding the coarse product, it is filtered through a 300-mesh filter to obtain the finished modified solvent-based ink for PVC film coating.

[0033] Example 6 A modified solvent-based ink for coating PVC face masks and its preparation method: First, the modified solvent-based ink for coating PVC face masks comprises the following raw materials in parts by weight: 55 parts of the main resin solution (30% solid content binary chloroacetic acid resin-ethyl acetate solution); 18 parts of the dual-modified synergistic prepolymer prepared in Example 3; 30 parts of pigment titanium dioxide (R-996, Longbai Group); Anti-settling agent: 0.5 parts of fumed silica (Aerosil 200, Evonik); Dispersant BYK-110 (BYK, Germany) 2.0 parts; 20 parts of mixed solvent (prepared by mixing butanone and butyl acetate in a volume ratio of 6:4).

[0034] Then, the method for preparing modified solvent-based inks for coating PVC masks includes the following steps: Step S1: Preparation of color paste: Weigh each raw material according to the weight parts, mix and stir 40% of the total amount of the main resin liquid (30% solid content of binary chloroacetic acid resin-ethyl acetate solution), dispersant BYK-110 (Germany BYK), and pigment titanium dioxide (R-996, Longbai Group) for 30 minutes to obtain color paste; Step S2: High-speed dispersion: At a stirring speed of 1000 rpm, the dual-modified synergistic prepolymer prepared in Example 3 was added to the remaining main resin liquid and mixed for 30 min to obtain a mixed component; Step S3: Paint mixing: Add the color paste prepared in step S1, the anti-settling fumed silica (Aerosil 200, Evonik), and the mixed solvent (butanone and butyl acetate prepared in a volume ratio of 6:4) to the mixed components, mix and stir for 10 minutes to obtain the crude product; Step S4: Filtration and Packaging: After grinding the coarse product, it is filtered through a 300-mesh filter to obtain the finished modified solvent-based ink for PVC film coating.

[0035] Comparative Example 2 Comparative Example 2 served as the control group for Example 5. The dual-modified synergistic prepolymer prepared in Example 2 was replaced with an equal weight of the prepolymer prepared in Comparative Example 1. The remaining raw materials, raw material amounts, and preparation steps remained consistent with those in Example 5, ultimately yielding a modified solvent-based ink.

[0036] Comparative Example 3 Comparative Example 3 served as the control group for Example 5. The dual-modified synergistic prepolymer prepared from the raw material in Example 2 of Example 5 was removed, while the remaining raw materials, raw material amounts, and preparation steps remained consistent with those in Example 5, ultimately yielding the modified solvent-based ink.

[0037] Test Example 1 The modified solvent-based inks prepared in Examples 4 to 6 and Comparative Examples 2 to 3 were subjected to performance tests. The performance test process is as follows, and the test results are shown in Table 1: (1) Anti-blocking test: Method: PVC sheets printed with the modified solvent-based inks prepared in Examples 4-6 and Comparative Examples 2-3 were cut into 5cm × 5cm pieces. Two sheets were stacked with their ink sides facing each other and placed in a constant temperature chamber (60℃, simulating the temperature of a shipping container). A 500g weight was applied and the sheets were left for 24 hours. After cooling, the sheets were manually peeled off.

[0038] Scoring criteria: Level 5 (natural peeling, no sound); Level 4 (slight adhesion, slight peeling sound, no damage to the ink layer); Level 3 (adhesion, tearing sound during peeling, slight whitening of the ink layer); Level 2 (severe adhesion, damaged ink layer); Level 1 (complete fusion).

[0039] (2) Stain resistance (colorfastness) test: Method: Red lipstick and oil-based marker were applied to the surface of the cured ink layers of the modified solvent-based inks prepared in Examples 4-6 and Comparative Examples 2-3, respectively. After standing for 1 hour, the ink layers were wiped with a dry paper towel and then wiped with a cotton ball soaked in alcohol.

[0040] Rating criteria: Level 5 (Completely erasable, no trace); Level 4 (Faint traces visible); Level 3 (Obvious color marks); Level 2 (Dark stains remain); Level 1 (Stains completely penetrated and cannot be erased).

[0041] (3) Flexibility and adhesion (bending test): Method: The soft PVC film coated with the modified solvent-based inks prepared in Examples 4 to 6 and Comparative Examples 2 to 3 was folded 180° and folded repeatedly 50 times.

[0042] Scoring criteria: Pass (no cracks, peeling, or whitening of the ink layer); Fail (fine cracks or peeling of the ink layer).

[0043] (4) Recoatability (interlayer adhesion): Method: After the first coat of ink has dried to surface (20 min at 25°C), apply the second coat of the same ink after a 10-minute interval. After drying (60 min at 60°C), check the leveling and interlayer adhesion (tape pull).

[0044] Rating: Pass (good leveling, no delamination between layers); Fail (pinholes appear or layers easily peel off).

[0045] Table 1 Test Results Analysis of the data in Table 1: (1) As can be seen from Comparative Example 3, under the same main resin liquid, pigment, additives and process conditions, the lack of dual-modified synergistic prepolymer will result in: the anti-blocking performance will decrease from level 4-5 in the example to level 1; the stain resistance will decrease from level 4-5 in the example to level 1; and the bending performance will change from qualified to unqualified. This shows that the prepolymer plays a decisive role in improving the overall performance.

[0046] (2) A comparison between Example 5 and Comparative Example 2 shows that, under the same formulation and preparation conditions, simply replacing the "double-modified synergistic prepolymer" with the "PDMS-OH prepolymer replaced by dimerol" will cause the following to occur: the anti-blocking performance will decrease from level 5 to level 3; the stain resistance will decrease from level 5 to level 2; while the bending performance will still be acceptable and the recoating performance will still pass. Therefore, it can be confirmed that the double-modified synergistic prepolymer significantly improves anti-blocking and stain resistance compared to the control prepolymer, and this improvement does not stem from differences in recoating performance.

[0047] (3) Examples 4 to 6 show that after introducing the dual-modified synergistic prepolymer, the system can simultaneously achieve high anti-blocking and high stain resistance, while maintaining the bending qualification and recoating pass; among them, Examples 5 and 6 reached the highest level (level 5) of each scoring item, while Example 4 was slightly lower (level 4).

[0048] It should be noted that, in this document, terms such as “comprising,” “including,” or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0049] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A modified solvent-based ink for coating PVC face masks, characterized in that, Including the following parts by weight of raw materials: 45-55 parts of main resin solution; 12–18 parts of the dual-modified synergistic prepolymer; 20-30 parts pigment; Anti-settling agent 0.2-0.5 parts; Dispersant 0.5–2.0 parts; Mixed solvent 10-20 parts.

2. The modified solvent-based ink for coating PVC face masks according to claim 1, characterized in that, The main resin solution is a binary chloroacetic acid resin-ethyl acetate solution with a solid content of 30%.

3. The modified solvent-based ink for coating PVC face masks according to claim 1, characterized in that, The pigment is titanium dioxide.

4. The modified solvent-based ink for coating PVC face masks according to claim 1, characterized in that, The anti-settling agent is organic bentonite or fumed silica.

5. The modified solvent-based ink for coating PVC face masks according to claim 1, characterized in that, The dispersant is BYK-163 or BYK-110.

6. The modified solvent-based ink for coating PVC face masks according to claim 1, characterized in that, The mixed solvent is prepared by mixing butanone and butyl acetate in a volume ratio of 6:

4.

7. The modified solvent-based ink for coating PVC face masks according to claim 1, characterized in that, The dual-modified synergistic prepolymer is prepared by the following steps: Step A1: Mix the dimerol and hydroxyl-terminated polydimethylsiloxane, and dehydrate them at 105-110℃ and -0.098MPa vacuum for 1.5-2.0h to obtain the mixture; Step A2: Cool the mixture to 55-60℃, add isophorone diisocyanate to it, and then add bismuth neodecanoate to the system. Heat the system to 80-85℃ and react for 3-5 hours. After the reaction is complete, the copolymer is obtained. Step A3: Cool the copolymer to 45-50°C, add methyl ethyl ketone oxime dropwise, and then maintain the temperature for the reaction until the infrared spectrum reaches 2270 cm⁻¹. -1 The -NCO characteristic peak disappears at the point, yielding the product; Step A4: Add ethyl acetate to the product to adjust the solid content to 50%–60%. After completion, the dual-modified synergistic prepolymer is obtained.

8. The modified solvent-based ink for coating PVC face masks according to claim 7, characterized in that, The ratio of the following components is: dimerol, hydroxyl-terminated polydimethylsiloxane, isophorone diisocyanate, bismuth neodecanoate, and methyl ethyl ketone oxime: 80g: 20g: 50-55g: 4-5g: 22-25g.

9. A method for preparing a modified solvent-based ink for coating PVC face masks according to any one of claims 1 to 8, characterized in that, Includes the following steps: Step S1: Weigh each raw material according to the weight parts, mix and stir 40% of the total amount of main resin liquid, dispersant and pigment for 15-30 minutes to obtain color paste; Step S2: Add the dual-modified synergistic prepolymer to the remaining main resin liquid at a stirring speed of 800-1000 rpm, and mix for 15-30 min to obtain the mixed components; Step S3: Add the color paste, anti-settling agent and mixed solvent prepared in step S1 to the mixed components, mix and stir for 5-10 minutes to obtain the crude product; Step S4: After grinding the coarse product, filter it through a 300-mesh filter to obtain the finished modified solvent-based ink for PVC film coating.

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