PVC cross-linking agent with high peel strength

Abstract

The invention discloses a PVC cross-linking agent with high peel strength. The PVC cross-linking agent comprises the following raw materials: 35-45 parts of toluene diisocyanate (TDI) (T80); 55 to 65 parts of a plasticizer dioctyl phthalate (DOP); 2 parts of a stabilizer; 2 parts of a flame retardant; and 2 parts of a terminating agent. After the PVC cross-linking agent and a PVC fiber synthetic leather product are used and formed for 3 months, the peel strength can reach 162N, the adhesive force of a PVC plastisol coating and a substrate made of polyester, polyamide or aramid fiber, woven cloth, warp knitted cloth, coated cloth and other fabrics can be improved, the softness is good, the opening time is long, and the service life of a terminal product is as long as 3 years. The PVC cross-linking agent provided by the invention is suitable for preparing lamp box cloth, advertising cloth, kayak cloth, tent cloth, swimming pool cloth and the like, and is also suitable for products with high requirements on bonding strength and hardness, such as conveying belts, industrial belts, gear belts, elastic pipelines, hoses and the like.

Description

Technical Field

[0001] The invention discloses a high peel strength PVC crosslinking agent and relates to the field of fine chemical product crosslinking agents. Background Art

[0002] As one of the traditional synthetic leathers, PVC fiber synthetic leather has the disadvantages of poor adjustability and single performance due to the limitations of raw material types and process methods, which limits its scope of use. PVC cross-linking agent, also known as (PVC-U) adhesive, can greatly improve the performance of PVC synthetic leather. According to the current market situation, the invention of PVC cross-linking agent with high peel strength, UV resistance, heat resistance, water resistance, and antibacterial properties is the best means to improve the softness, tear resistance, peel strength, open time, environmental protection and other key indicators of leather products.

[0003] At present, only a few studies are aimed at improving the peel strength of PVC crosslinkers. Patent 1 "A PVC adhesive and its preparation method and application" (CN 112029446 A) discloses a PVC adhesive, which uses toluene diisocyanate TDI and plasticizers DINP and DPHP for polymerization reaction. No organic volatiles are generated during the production process. It is environmentally friendly, has strong adhesion and hydrolysis resistance. It is used in the preparation of PV synthetic leather to increase the durability of the product and extend the service life of the product. However, there is a disadvantage of long plasticization time. Patent 2 "A PVC crosslinker based on TDI-DBP" (CN 112300518 A) discloses a PVC crosslinker based on TDI-DBP and its preparation method. 2,4-diisocyanatotoluene ester T100 and dibutyl phthalate DBP are used for polymerization to prepare the PVC crosslinker. It has the characteristics of good peel strength, long development time, high tear strength and good softness, but its environmental performance is poor and it is not suitable for children's toys, medical and other fields. Summary of the invention

[0004] It can be seen from the above-mentioned patent disclosure that the existing technology prolongs the plasticization time and reduces its environmental protection in the process of improving the peel strength of the PVC crosslinking agent. In order to solve the shortcomings and deficiencies in the above-mentioned prior art, the present invention provides a high peel strength PVC crosslinking agent and a preparation method thereof, which has the characteristics of fast plasticization and good environmental protection performance while taking into account high peel strength.

[0005] To achieve the above object, the PVC crosslinking agent disclosed in the present invention comprises the following components: TDI (T80) 35~45 parts; DOP (plasticizer) 55~65 parts; 2 parts of hindered amine light stabilizer; 2 parts of hindered phenol antioxidant, preferably antioxidant 300; 1 part of flame retardant, preferably tri(2-carboxyethyl)phosphine TCEP; 2 parts of terminator, preferably acetone thiosemicarbazone.

[0006] The viscosity of the PVC cross-linking agent prepared according to the above components is 3000~7000 (mPa·s).

[0007] Based on the above PVC crosslinking agent, the present invention also discloses a bulk polymerization method for preparing the PVC crosslinking agent, comprising the following steps: (1) Add TDI (T80) and DOP into the reactor container and stir in a sealed container at room temperature for 15 h until the mixture is uniformly mixed; (2) Add other auxiliary materials to (1), raise the temperature to 50 °C, and continue stirring for 1-2 h; (3) Pour the raw materials in (2) into a reaction kettle, seal it at 100-120 °C, and carry out polymerization reaction for 24 h; (4) After the reaction is completed, cool the reaction vessel to room temperature, pour out the product in the reactor, and seal it.

[0008] In summary, the present invention has the following advantages: The PVC crosslinking agent disclosed in the present invention uses toluene diisocyanate T80 as a main raw material, so that the PVC crosslinking agent can have better bonding ability with smooth synthetic fibers, and the peeling strength of the PVC fiber synthetic leather product can reach 162N after being used for molding for 3 months; The PVC crosslinking agent disclosed in the present invention uses dioctyl phthalate DOP as a plasticizer, which ensures the peeling strength of the product and has the characteristics of fast plasticization. The viscosity of the product can reach 3994 mPa·s after 10 minutes. Implementation

[0009] In order to better illustrate the purpose, technical scheme and advantages of the present invention, the present invention will be further illustrated in conjunction with specific embodiments below. It is particularly noted that the embodiments of the present invention are only used to illustrate the technical effects of the present invention, rather than to limit the scope of protection of the present invention. The raw materials used in the embodiments can all be obtained by commercial purchase. Example

[0010] In an optimized embodiment of the present invention, the PVC crosslinking agent comprises the following components: 35 parts of toluene diisocyanate TDI (T80), 55 parts of plasticizer dibutyl phthalate DOP, 2 parts of stabilizer hindered amine light stabilizer, 2 parts of hindered phenol antioxidant (antioxidant 300), 1 part of flame retardant tris (2-carboxyethyl) phosphine TCEP, and 2 parts of terminator acetone thiosemicarbazone.

[0011] The preparation of PVC crosslinking agent adopts bulk polymerization method, which includes the following steps: (1) Add T80 and DOP into the reactor container and stir in a sealed container at room temperature for 15 h until the mixture is uniform; (2) Add other auxiliary materials to (1), raise the temperature to 50 °C, and continue stirring for 1-2 h; (3) Pour the raw materials in (2) into a reaction kettle, seal it at 100-120 °C, and carry out polymerization reaction for 24 h; (4) After the reaction is completed, cool the reaction vessel to room temperature, pour out the product in the reactor, and seal it. Example

[0012] In an optimized embodiment of the present invention, the PVC crosslinking agent comprises the following components: 45 parts of toluene diisocyanate TDI (T80), 55 parts of plasticizer dibutyl phthalate DOP, 2 parts of stabilizer hindered amine light stabilizer, 2 parts of hindered phenol antioxidant (antioxidant 300), 1 part of flame retardant tris (2-carboxyethyl) phosphine TCEP, and 2 parts of terminator acetone thiosemicarbazone.

[0013] The preparation method and steps of the cross-linking agent are consistent with those in Example 1. Example

[0014] In an optimized embodiment of the present invention, the PVC crosslinking agent comprises the following components: 35 parts of toluene diisocyanate TDI (T80), 65 parts of plasticizer dioctyl phthalate DOP, 2 parts of stabilizer hindered amine light stabilizer, 2 parts of hindered phenol antioxidant (antioxidant 300), 1 part of flame retardant tris (2-carboxyethyl) phosphine TCEP, and 2 parts of terminator acetone thiosemicarbazone.

[0015] The preparation method and steps of the cross-linking agent are consistent with those in Example 1.

[0016] Comparative Example 1 A high peel strength PVC crosslinking agent, which is different from Example 1 only in that the hydrothermal reaction temperature is 120°C.

[0017] Comparative Example 2 A high peel strength PVC crosslinking agent, which is different from Example 2 only in that the hydrothermal reaction temperature is 120°C.

[0018] Comparative Example 3 A high peel strength PVC crosslinking agent, which is different from Example 3 only in that the hydrothermal reaction temperature is 120°C.

[0019] Experimental Example 1: Adhesion Test The PVC crosslinking agents of Examples 1 to 3 and Comparative Examples 1 to 3 were added to PVC resin for bonding of PVC synthetic leather (used to bond the PVC layer and the base fabric according to the existing method), and the viscosity performance of PVC synthetic leathers prepared with different PVC crosslinking agents was tested respectively, and each test was repeated three times to take the average value.

[0020] Experimental method: PVC resin containing the crosslinking agent of the present invention is added to the PVC layer and the base fabric, the amount of the crosslinking agent added to the PVC resin is 3%, and the viscosity of the mixture is measured by using an NDJ-1 type viscometer every 10 minutes after the addition of the crosslinking agent, and the viscosity unit is mPa·s; the viscosity changes of different groups of crosslinking agents within 1 hour after the addition of the crosslinking agent are shown in Table 1: Table 1: Adhesion test results

[0021] Experimental conclusion: The product prepared according to the formula and method of the present invention has a viscosity of 3994 mPa·s in 10 minutes, has the characteristic of fast plasticization, and the viscosity changes within 1 hour from 3800 to 6350 mPa·s at most. The above experimental results show that the viscosity of the product obtained in Comparative Example 3 is the highest, which can reach 6963 mPa·s after 1 hour, and has the characteristic of high viscosity.

[0022] Experimental Example 2: Relationship between product molding time and peel strength Experimental method: The PVC crosslinking agents of Examples 1 to 3 and Comparative Examples 1 to 3 were added to PVC resin for bonding of PVC synthetic leather (used to bond PVC layer and base fabric according to the existing method). The amount of crosslinking agent added was 3%. The peel strength test was performed every 1 month for a total of 3 months. Each test was repeated three times and the average value was taken. The specific steps are as follows: Immediately after the cross-linking agent is added, the mixture is evenly coated with a scraper on 800dtex*800dtex PVC fiber synthetic leather, 800dtex in both warp and weft directions, and woven fabric with a weaving density of 20*20 strands / inch. The coating weight per square meter is controlled at 200g, and plasticized in an oven at 180°C for 5 minutes. After plasticization, it is cooled. The test results are shown in Table 2: Table 2: Peel strength test results of groups with different molding times

[0023] Experimental conclusion: The crosslinking agents of Examples 1 to 3 of the present invention and Comparative Examples 1 to 3 have been increasing peel strength for a long time after being used with PVC fiber synthetic leather products, with the highest time reaching more than 120 months and the highest peel strength reaching 162 N. The PVC crosslinking agent of the present invention has low cost and high cost performance.

[0024] Experimental Example 3: Environmental Limitation Detection Testing method: SGS testing. The present invention is implemented with reference to German hazardous substance regulations and relevant EU directives. The product complies with the amendment directive of Annex II of the EU RoHS Directive 2011 / 65EU and the limit requirements of (EU) 2015 / 863.

Claims

1. A high peel strength PVC crosslinking agent, characterized in that Contains the following components: 35~45 parts of TDI (T80), 55~65 parts of plasticizer, 2 parts of stabilizer, 2 parts of hindered phenol antioxidant, 1 part of flame retardant, and 2 parts of terminator; The preparation method of the high peel strength PVC crosslinking agent comprises the following steps: (1) Add TDI (T80) and DOP into the reactor container and stir in a sealed container at room temperature for 15 h until the mixture is uniformly mixed; (2) Add other auxiliary materials to (1), raise the temperature to 50 °C, and continue stirring for 1-2 h; (3) Pour the raw materials in (2) into a reaction kettle, seal it at 100-120 °C, and carry out polymerization reaction for 24 h; (4) After the reaction is completed, cool the reaction vessel to room temperature, pour out the product in the reactor, and seal it.

2. The high peel strength PVC crosslinking agent according to claim 1, characterized in that: The TDI is T80 (a mixture of 80% by weight of 2,4-toluene diisocyanate and 20% by weight of 2,6-toluene diisocyanate); the plasticizer is dioctyl phthalate DOP; the stabilizer is a hindered amine light stabilizer; the hindered phenol antioxidant is antioxidant 300; the flame retardant is tris(2-carboxyethyl)phosphine TCEP; and the terminator is acetone thiosemicarbazone.

3. The PVC crosslinking agent according to claim 1, characterized in that The viscosity of the crosslinking agent is 3000~7000mPa·s. When added to PVC resin at a 3% addition in later applications, its peel strength can reach up to 162N.

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