Castor oil modified cross-linking agent as well as preparation method and application thereof

Abstract

The invention provides a castor oil modified cross-linking agent as well as a preparation method and application thereof, and belongs to the technical field of photovoltaic materials. The castor oil modified cross-linking agent is prepared from the following raw materials: polyol, an acidic compound, diisocyanate and a coupling agent, the polyol comprises castor oil; the molar percentage content of castor oil in the polyhydric alcohol is greater than or equal to 75 mol% based on the molar percentage content of the polyhydric alcohol being 100 mol%. The preparation method comprises the following steps: mixing polyol, an acidic compound and a catalyst, and reacting to obtain castor oil modified polyol; carrying out reaction on the castor oil modified polyol and diisocyanate to obtain an isocyanate group terminated prepolymer; and reacting the isocyanate-terminated prepolymer with a coupling agent to obtain the castor oil modified cross-linking agent. The castor oil modified cross-linking agent with excellent performance is prepared by designing the preparation raw materials of the castor oil modified cross-linking agent, and then the packaging adhesive film with excellent performance is prepared.

Description

Technical Field

[0001] The present invention belongs to the technical field of photovoltaic materials, and particularly relates to a castor oil modified crosslinking agent, a preparation method thereof and an application thereof. Background Art

[0002] The photovoltaic industry's adhesive films adopt two major categories: EVA (ethylene-vinyl acetate copolymer) and POE (polyolefin elastomer). POE has good ultraviolet resistance, and EVA has high bonding strength and low cost. In order to combine the advantages of both, a three-layer adhesive film EVA-POE-EVA adhesive film, namely EPE, has emerged. This kind of material takes into account the good ultraviolet resistance of POE, and at the same time improves the bonding strength between the product and the battery chip while reducing the cost. However, a defect appears at the same time, that is, the problem of interlayer slippage will occur during the preparation of the EPE adhesive film.

[0003] To solve this problem, there are several common solutions on the market. Materials using inorganic hybrid modified coupling agents are used to improve the crosslinking of EVA and POE, or monomer materials of acrylate esters are used as bridging agents, and the characteristics of rapid crosslinking of the monomer structure are utilized to enhance the crosslinking during the preparation process. Although both can improve the problem of interlayer slippage to a certain extent, there are also certain potential hazards. For example, in the case of inorganic hybrid materials, hydrolysis will occur in the long-term high-temperature water resistance of the adhesive film, resulting in the failure of the adhesive film bonding. Due to the small molecular weight of acrylate esters and inevitable residues, long-term outdoor use will be similar to the migration of plasticizers, and long-term accumulation will still reduce the bonding fastness.

[0004] Therefore, how to provide a crosslinking agent that can enhance the bonding fastness between the EVA layer and the POE layer, and then prepare an EPE adhesive film with a higher interlayer bonding strength has become an urgent technical problem to be solved at present. Summary of the Invention

[0005] Aiming at the deficiencies of the prior art, the purpose of the present invention is to provide a castor oil modified crosslinking agent, a preparation method thereof and an application thereof. The present invention designs the preparation raw materials of the castor oil modified crosslinking agent, and prepares a castor oil modified crosslinking agent with excellent performance. As a crosslinking agent between the strong EVA layer and the POE layer, the castor oil modified crosslinking agent can enhance the bonding fastness between the EVA layer and the POE layer, solve the problem of interlayer slippage, and improve the peel strength of the EPE adhesive film.

[0006] To achieve this purpose, the present invention adopts the following technical solutions:

[0007] In the first aspect, the present invention provides a castor oil modified crosslinking agent, and the preparation raw materials of the castor oil modified crosslinking agent include the following components:

[0008] Polyol, acidic compound, diisocyanate, coupling agent;

[0009] The polyol includes castor oil;

[0010] Based on the molar percentage of the polyol being 100 mol%, the molar percentage of castor oil in the polyol ≥ 75 mol%;

[0011] The acidic compound includes dibasic acid and / or dibasic anhydride.

[0012] By designing the raw materials for preparing the castor oil modified crosslinking agent, the present invention prepares a castor oil modified crosslinking agent with excellent performance. As a crosslinking agent between the EVA layer and the POE layer, this castor oil modified crosslinking agent can enhance the bonding fastness between the EVA layer and the POE layer, solve the problem of interlayer slippage, and improve the comprehensive performance of the EPE film.

[0013] Furthermore, by using castor oil, the present invention prepares a crosslinking agent containing a castor oil structure, making the polarity of this crosslinking agent similar to that of POE particles. At the same time, a certain amount of unsaturated bonds exist in this crosslinking agent. During the subsequent processing of preparing the EPE film, the unsaturated bonds in the castor oil modified crosslinking agent can crosslink with POE particles, resulting in a relatively high bonding fastness between the castor oil modified crosslinking agent and the POE layer. At the same time, by using a coupling agent, alkoxy groups are introduced into the castor oil modified crosslinking agent. During the subsequent processing of preparing the EPE film, the hydrolysis and release of the coupling agent groups will cause the hydrolyzed coupling agent groups to rivet on the EVA interface, resulting in a relatively high bonding fastness between the castor oil modified crosslinking agent and the EVA layer. Therefore, in the present invention, by designing the raw materials for preparing the castor oil modified crosslinking agent, a castor oil modified crosslinking agent with excellent performance is prepared. A three-dimensional crosslinked network structure is formed between the EVA layer and the POE through the castor oil groups and coupling agent groups in the castor oil modified crosslinking agent, improving the bonding fastness between the EVA layer and the POE layer, solving the problem of interlayer slippage, and improving the peel strength of the EPE film.

[0014] A large number of unsaturated bonds exist in the molecular chain segments of the castor oil modified crosslinking agent provided by the present invention. Therefore, its residue rate is lower than that of the acrylate material crosslinking agent, and at the same time its molecular weight is larger, so its migration property is smaller.

[0015] In the present invention, by controlling the content of castor oil in the polyol within a specific range, a castor oil modified crosslinking agent with excellent performance is obtained. If the content of castor oil in the polyol is too low, the polarity of the prepared castor oil modified crosslinking agent is slightly different from that of POE particles, and the bonding strength between the castor oil modified crosslinking agent and the POE layer is relatively low.

[0016] It should be noted that the CAS number of the castor oil used in the present invention is 8001-79-4, the molar mass is 933.45 g / mol, and each castor oil molecule contains 3 hydroxyl groups.

[0017] In the present invention, the amount of substance of castor oil = mass of castor oil ÷ molar mass of castor oil; the amount of substance of hydroxyl groups provided by castor oil = 3 × amount of substance of castor oil.

[0018] In the present invention, based on the molar percentage content of the polyol being 100 mol%, the molar percentage content of castor oil in the polyol ≥ 75 mol%, for example, it can be 75 mol%, 78 mol%, 80 mol%, 81 mol%, 83 mol%, 86 mol%, 88 mol%, 90 mol%, 93 mol%, 96 mol%, 98 mol% or 100 mol% etc.

[0019] In the present invention, the molar percentage content of castor oil in the polyol = amount of substance of castor oil ÷ (amount of substance of castor oil + amount of substance of small molecule polyol) × 100%.

[0020] The following are the preferred technical solutions of the present invention, but do not limit the technical solutions provided by the present invention. Through the following preferred technical solutions, the purpose and beneficial effects of the present invention can be better achieved and realized.

[0021] As a preferred technical solution of the present invention, the coupling agent includes an amino silane coupling agent.

[0022] In the present invention, by selecting a coupling agent containing amino groups, and further through the reaction between amino groups and isocyanate groups, the coupling agent is chemically grafted and fixed in the castor oil modified crosslinking agent.

[0023] Preferably, the amino silane coupling agent is selected from any one or a combination of at least two of γ-aminopropyltriethoxysilane (KH550), N-(β-aminoethyl)-γ-aminopropyltrimethoxysilane (KH572), 3-aminopropyltrimethoxysilane (APS), N-(β-aminoethyl)-γ-aminopropyltriethoxysilane (KH791), γ-aminopropylmethyldiethoxysilane or γ-aminopropylmethyldimethoxysilane.

[0024] As a preferred technical solution of the present invention, the coupling agent includes a combination of N-(β-aminoethyl)-γ-aminopropyltrimethoxysilane (KH572) and γ-aminopropyltriethoxysilane (KH550).

[0025] Preferably, the molar ratio of N-(β-aminoethyl)-γ-aminopropyltrimethoxysilane (KH572) to γ-aminopropyltriethoxysilane (KH550) is 1:(0.5 - 2), for example, it can be 1:0.5, 1:0.6, 1:0.8, 1:1, 1:1.2, 1:1.4, 1:1.6, 1:1.8 or 1:2, etc.

[0026] In the present invention, by preferably using the combination of N-(β-aminoethyl)-γ-aminopropyltrimethoxysilane (KH572) and γ-aminopropyltriethoxysilane (KH550) as the coupling agent and controlling the molar ratio of the two within a specific range, the comprehensive performance of the castor oil-modified crosslinking agent is further optimized and improved.

[0027] As a preferred technical solution of the present invention, the polyol further includes a small molecule diol.

[0028] Preferably, the small molecule diol is selected from any one or a combination of at least two of 1,3-propanediol, 1,4-butanediol, ethylene glycol or diethylene glycol.

[0029] As a preferred technical solution of the present invention, the dibasic acid includes 1,6-hexanedioic acid and / or isophthalic acid.

[0030] Preferably, the dibasic anhydride is selected from phthalic anhydride and / or maleic anhydride.

[0031] As a preferred technical solution of the present invention, the diisocyanate is selected from any one or a combination of at least two of isophorone diisocyanate (IPDI), hexamethylene diisocyanate (HDI), dicyclohexylmethane diisocyanate (HMDI), toluene diisocyanate (TDI) or diphenylmethane diisocyanate (MDI).

[0032] As a preferred technical solution of the present invention, the raw materials for preparing the castor oil-modified crosslinking agent further include a catalyst.

[0033] Preferably, the catalyst includes tetrabutyl titanate and / or tetraisopropyl titanate.

[0034] In a second aspect, the present invention provides a method for preparing the castor oil-modified crosslinking agent as described in the first aspect, and the preparation method includes the following steps:

[0035] (1) Mix the polyol, acidic compound and catalyst, and react to obtain a castor oil-modified polyol;

[0036] (2) React the castor oil-modified polyol obtained in step (1) with the diisocyanate to obtain an isocyanate group-terminated prepolymer;

[0037] (3) The isocyanate group-terminated prepolymer obtained in step (2) reacts with a coupling agent to obtain the castor oil-modified crosslinking agent.

[0038] In the present invention, the reaction process in step (1) is as follows: under the action of a catalyst, the hydroxyl groups in the polyols (castor oil and small molecule polyols) react with the carboxyl groups or acid anhydride groups in the acidic compound to obtain a castor oil-modified polyol; in step (2), the hydroxyl groups in the castor oil-modified polyol react with the isocyanate groups of the diisocyanate to obtain an isocyanate group-terminated prepolymer; and as described below, since the molar ratio of the hydroxyl groups in the castor oil-modified polyol to the isocyanate groups in the diisocyanate is 1:(1.3 - 1.5), that is, the amount of the diisocyanate used is relatively large, it is confirmed that an isocyanate group-terminated prepolymer can be obtained; in step (3), the isocyanate groups in the isocyanate group-terminated prepolymer react with the amino groups in the coupling agent, chemically grafting and fixing the coupling agent in the castor oil-modified crosslinking agent to obtain the castor oil-modified crosslinking agent.

[0039] As a preferred technical solution of the present invention, the molar ratio of the polyol to the acidic compound in step (1) is (1.1 - 1.2):1, and for example, it can be 1.1:1, 1.11:1, 1.12:1, 1.13:1, 1.14:1, 1.15:1, 1.16:1, 1.17:1, 1.18:1, 1.19:1 or 1.12:1, etc.

[0040] Preferably, based on the mass percentage of the polyol in step (1) being 100%, the mass percentage of the catalyst is 0.3 - 0.8%, and for example, it can be 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, or 0.8%, etc.

[0041] Preferably, the temperature of the reaction in step (1) is 160 - 230 °C, and for example, it can be 160 °C, 170 °C, 180 °C, 190 °C, 200 °C, 210 °C, 220 °C or 230 °C, etc.

[0042] Preferably, the acid value of the castor oil-modified polyol is ≤5 mgKOH / g, and for example, it can be 1 mgKOH / g, 1.5 mgKOH / g, 2 mgKOH / g, 2.5 mgKOH / g, 3 mgKOH / g, 3.5 mgKOH / g, 4 mgKOH / g, 4.5 mgKOH / g or 5 mgKOH / g, etc.

[0043] It should be noted that the test method for the acid value of the castor oil-modified polyol is acid-base titration.

[0044] Preferably, the reaction in step (1) is carried out in an atmosphere of a protective gas.

[0045] Preferably, the protective gas atmosphere includes nitrogen.

[0046] As a preferred technical solution of the present invention, the molar ratio of the hydroxyl group in the castor oil-modified polyol to the isocyanate group in the diisocyanate in step (2) is 1:(1.3 - 1.5), for example, it can be 1:1.3, 1:1.32, 1:1.34, 1:1.36, 1:1.38, 1:1.4, 1:1.42, 1:1.44, 1:1.46, 1:1.48 or 1:1.5, etc.

[0047] It should be noted that in the present invention, the test method for the molar amount of the hydroxyl group in the castor oil-modified polyol is: GBT 7193.2 - 1987 "Determination Method for Hydroxyl Value of Unsaturated Polyester Resins".

[0048] Preferably, the temperature of the reaction in step (2) ≤ 80°C, for example, it can be 50°C, 52°C, 55°C, 57°C, 60°C, 63°C, 66°C, 69°C, 72°C, 75°C, 78°C or 80°C, etc.

[0049] Preferably, the hydroxyl value of the isocyanate group-terminated prepolymer ≤ 5mgKOH / g, for example, it can be 1mgKOH / g, 1.5mgKOH / g, 2mgKOH / g, 2.5mgKOH / g, 3mgKOH / g, 3.5mgKOH / g, 4mgKOH / g, 4.5mgKOH / g or 5mgKOH / g, etc.

[0050] It should be noted that the test method for the hydroxyl value of the isocyanate group-terminated prepolymer is: GBT 7193.2 - 1987 "Determination Method for Hydroxyl Value of Unsaturated Polyester Resins".

[0051] As a preferred technical solution of the present invention, the molar ratio of the amino group in the coupling agent to the isocyanate group in the isocyanate group-terminated prepolymer in step (3) is (1 - 1.05):1, for example, it can be 1:1, 1:1.01, 1.02:1, 1.03:1, 1.04:1 or 1.05:1, etc.

[0052] It should be noted that in the present invention, the test method for the molar amount of the isocyanate group in the isocyanate group-terminated prepolymer is: HGT 2409 - 1992 "Determination of Isocyanate Group Content in Polyurethane Prepolymers".

[0053] Preferably, the temperature of the reaction in step (3) is ≤ 70°C, for example, it can be 50°C, 52°C, 54°C, 56°C, 58°C, 60°C, 62°C, 64°C, 66°C, 68°C or 70°C, etc.

[0054] Based on the mass percentage of the castor oil modified crosslinking agent obtained after the reaction in step (3) being 100%, the mass percentage of isocyanate groups in the castor oil modified crosslinking agent is ≤0.1%, for example, it can be 0.01%, 0.02%, 0.03%, 0.04%, 0.05%, 0.06%, 0.07%, 0.08%, 0.09% or 0.1%, etc.

[0055] It should be noted that in the present invention, the test method for the mass percentage of isocyanate groups in the castor oil modified crosslinking agent is: HGT 2409-1992 "Determination of Isocyanate Group Content in Polyurethane Prepolymers"

[0056] As a preferred technical solution of the present invention, the preparation method of the castor oil modified crosslinking agent specifically includes the following steps:

[0057] (1) In an inert gas atmosphere, a polyol, an acidic compound and a catalyst are mixed and reacted at 160-230 °C. When the acid value of the reaction product, castor oil modified polyol, is ≤5 mgKOH / g, the reaction is stopped;

[0058] Among them, the molar ratio of the polyol to the acidic compound is (1.1-1.2):1;

[0059] Based on the mass percentage of the polyol in step (1) being 100%, the mass percentage of the catalyst is 0.3-0.8%;

[0060] (2) The castor oil modified polyol obtained in step (1) reacts with a diisocyanate, and the reaction temperature is controlled ≤80 °C. When the hydroxyl value of the reaction product, isocyanate group-terminated prepolymer, is ≤5 mgKOH / g, the reaction is stopped;

[0061] Among them, the molar ratio of the castor oil modified polyol to the diisocyanate is 1:(1.3-1.5);

[0062] (3) The isocyanate group-terminated prepolymer obtained in step (2) reacts with a coupling agent, and the reaction temperature is controlled ≤70 °C. When the mass percentage of isocyanate groups in the product, castor oil modified crosslinking agent, is ≤0.1%, the reaction is stopped to obtain the castor oil modified crosslinking agent;

[0063] Among them, the molar ratio of the amino groups in the coupling agent to the isocyanate groups in the isocyanate group-terminated prepolymer is (1-1.05):1.

[0064] In the third aspect, the present invention provides a packaging adhesive film, which includes a first EVA layer, a POE layer and a second EVA layer stacked in sequence;

[0065] The material of the POE layer includes the castor oil modified crosslinking agent as described in the first aspect and POE particles.

[0066] Preferably, based on the mass percentage content of the POE material being 100%, the mass percentage content of the castor oil modified crosslinking agent is 1-3%, for example, it can be 1%, 1.2%, 1.4%, 1.6%, 1.8%, 2%, 2.2%, 2.4%, 2.6%, 2.8% or 3%, etc.

[0067] In the present invention, by controlling the content of the castor oil modified crosslinking agent in the POE material within a specific range, an encapsulation film with excellent comprehensive performance is prepared. If the amount of the castor oil modified crosslinking agent used is too small, the interlayer adhesion force of the prepared encapsulation film is low; if the amount of the castor oil modified crosslinking agent used is too large, it will not further improve the comprehensive performance of the encapsulation film, but will increase the production cost of the encapsulation film.

[0068] It should be noted that the present invention has no special restrictions on the materials of the first EVA layer and the second EVA layer, and commonly used materials in the art are applicable. Exemplarily, but not limited to: the materials of the first EVA layer and the second EVA layer include EVA particles and optionally a castor oil modified crosslinking agent.

[0069] At the same time, it should be noted that the materials of the first EVA layer, the second EVA layer, and the POE layer may each independently include additives such as antioxidants and ultraviolet absorbents. The present invention has no special restrictions on the specific selection of additives such as antioxidants and ultraviolet absorbents, and commonly used additives in the art are applicable.

[0070] Fourthly, the present invention provides a method for preparing the encapsulation film as described in the third aspect, and the preparation method includes the following steps:

[0071] The encapsulation film is prepared by electron beam irradiation or thermal baking after three-layer coextrusion and calendaring.

[0072] It should be noted that the present invention has no special restrictions on the process conditions of three-layer coextrusion and calendaring, electron beam irradiation or thermal baking, and the commonly used process conditions of three-layer coextrusion and calendaring, electron beam irradiation or thermal baking in the art are applicable.

[0073] Compared with the prior art, the present invention has the following beneficial effects:

[0074] (1) The present invention designs the raw materials for the preparation of the castor oil modified crosslinking agent. By using castor oil and coupling agent and controlling the content of castor oil in the polyol within a specific range, a castor oil modified crosslinking agent with excellent performance is prepared. Using this castor oil modified crosslinking agent as the crosslinking agent between the EVA layer and the POE layer can enhance the bonding strength between the EVA layer and the POE layer, solve the problem of interlayer slippage, and improve the peel strength of the EPE encapsulation film. The peel strength between the prepared EPE film and glass before 48 h of PCT is 70 - 89 N / cm, and the peel strength between the prepared EPE film and glass after 48 h of PCT is 32 - 46 N / cm. After cutting the prepared EPE film into 5 * 5 cm film pieces and boiling them in boiling water at 100 °C for 6 h and then taking them out, after cooling, they do not fall off.

[0075] (2) The present invention further optimizes and improves the comprehensive performance of the castor oil modified crosslinking agent by preferably using a combination of N-(β-aminoethyl)-γ-aminopropyltrimethoxysilane (KH572) and γ-aminopropyltriethoxysilane (KH550) as the coupling agent and controlling their molar ratio within a specific range. The peel strength between the prepared EPE film and glass before 48 h of PCT is 85 - 89 N / cm, and the peel strength between the prepared EPE film and glass after 48 h of PCT is 42 - 46 N / cm. After cutting the prepared EPE film into 5 * 5 cm film pieces and boiling them in boiling water at 100 °C for 6 h and then taking them out, after cooling, they do not fall off and there are no bubbles between the layers. Description of the Drawings

[0076] Figure 1 is the infrared spectrum of the castor oil modified polyol provided in step (1) of Example 1 of the present invention;

[0077] Figure 2 is the infrared spectrum of the isocyanate group-terminated prepolymer provided in step (2) of Example 1 of the present invention;

[0078] Figure 3 is the infrared spectrum of the castor oil modified crosslinking agent provided in step (3) of Example 1 of the present invention. Detailed Embodiments

[0079] The technical solution of the present invention will be further described below in conjunction with the drawings and through specific embodiments. Those skilled in the art should understand that the embodiments are only for helping to understand the present invention and should not be regarded as specific limitations to the present invention.

[0080] Example 1

[0081] This example provides a castor oil modified crosslinking agent and its preparation method. The preparation method of the castor oil modified crosslinking agent is as follows:

[0082] (1) In a nitrogen atmosphere, castor oil (10 mol), 1,3-propanediol (1.6 mol), 1,6-hexanedioic acid (10 mol) and tetrabutyl titanate were mixed and reacted at 200 °C. The acid value of the reaction product, castor oil-modified polyol, was measured to be 5 mg KOH / g, and the reaction was stopped;

[0083] Based on the mass percentage of castor oil and 1,3-propanediol being 100%, the mass percentage of tetrabutyl titanate was 0.8%;

[0084] (2) The castor oil-modified polyol obtained in step (1) was reacted with isophorone diisocyanate, and the reaction temperature was controlled at ≤80 °C. The hydroxyl value of the reaction product, isocyanate group-terminated prepolymer, was measured to be 5 mg KOH / g, and the reaction was stopped;

[0085] Among them, the molar ratio of the hydroxyl group in the castor oil-modified polyol to the isocyanate group in isophorone diisocyanate was 1:1.4;

[0086] (3) The isocyanate group-terminated prepolymer obtained in step (2) was reacted with an amino coupling agent, and the reaction temperature was controlled at ≤70 °C. The mass percentage of the isocyanate group in the product, castor oil-modified crosslinking agent, was measured to be 0.1%, and the reaction was stopped to obtain the castor oil-modified crosslinking agent;

[0087] Among them, the amino silane coupling agent was composed of N-(β-aminoethyl)-γ-aminopropyltrimethoxysilane and γ-aminopropyltriethoxysilane in a molar ratio of 1:1;

[0088] The molar ratio of the amino group in the amino coupling agent to the isocyanate group in the isocyanate group-terminated prepolymer was 1.02:1.

[0089] The infrared spectrum of the castor oil-modified polyol provided in step (1) of this example is as Figure 1 shown. It can be seen from Figure 1 that in the range of 3300 - 3600 cm -1 , there is a characteristic peak of the hydroxyl group, indicating that the castor oil-modified polyol still contains a hydroxyl group.

[0090] The infrared spectrum of the isocyanate group-terminated prepolymer provided in step (2) of this example is as Figure 2 shown. It can be seen from Figure 2 that for the isocyanate group-terminated prepolymer, near 2260 cm -1 , there is a characteristic peak of the residual -NCO group, indicating that the isocyanate group-terminated prepolymer still contains an isocyanate group, that is, the isocyanate group-terminated prepolymer is obtained; and in the range of 3300 - 3600 cm -1 , no characteristic peak of the hydroxyl group is found;

[0091] The infrared spectrum of the castor oil modified crosslinking agent provided in step (3) of this example is as Figure 3 shown. From the comparison between Figure 2 and Figure 3 , it can be seen that after the prepolymer capped with isocyanate groups reacts with the coupling agent, the characteristic peak of the -NCO group near 2260 cm -1 disappears, indicating that the prepolymer capped with isocyanate groups and the coupling agent have indeed undergone the above reaction, and the castor oil modified crosslinking agent has been successfully prepared.

[0092] Example 2

[0093] This example provides a castor oil modified crosslinking agent and its preparation method. The preparation method of the castor oil modified crosslinking agent is as follows:

[0094] (1) In a nitrogen atmosphere, castor oil (11.4 mol), 1,4-butanediol (0.6 mol), isophthalic acid (10 mol) and tetra-isopropyl titanate are mixed and reacted at 170 °C. The acid value of the reaction product, castor oil modified polyol, is measured to be 4.5 mg KOH / g, and the reaction is stopped;

[0095] Based on the mass percentage content of castor oil and 1,4-butanediol being 100%, the mass percentage content of tetra-isopropyl titanate is 0.8%;

[0096] (2) The castor oil modified polyol obtained in step (1) reacts with hexamethylene diisocyanate, and the reaction temperature is controlled ≤80 °C. The hydroxyl value of the reaction product, prepolymer capped with isocyanate groups, is measured to be 4.8 mg KOH / g, and the reaction is stopped;

[0097] Among them, the molar ratio of the hydroxyl group in the castor oil modified polyol to the isocyanate group in hexamethylene diisocyanate is 1:1.3;

[0098] (3) The prepolymer capped with isocyanate groups obtained in step (2) reacts with an amino coupling agent, and the reaction temperature is controlled ≤70 °C. When the mass percentage content of the isocyanate group in the product, castor oil modified crosslinking agent, is measured to be 0.08%, the reaction is stopped to obtain the castor oil modified crosslinking agent;

[0099] Among them, the amino-silane coupling agent is composed of N-(β-aminoethyl)-γ-aminopropyltrimethoxysilane and γ-aminopropyltriethoxysilane at a molar ratio of 1:0.8;

[0100] The molar ratio of the amino group in the amino coupling agent to the isocyanate group in the prepolymer capped with isocyanate groups is 1:1.

[0101] Example 3

[0102] This embodiment provides a castor oil-modified crosslinking agent and a preparation method thereof. The preparation method of the castor oil-modified crosslinking agent is as follows:

[0103] (1) In a nitrogen atmosphere, castor oil (11.5 mol), adipic acid (10 mol), and tetrabutyl titanate are mixed and reacted at 220 °C. The acid value of the reaction product, castor oil-modified polyol, is measured to be 4.6 mg KOH / g, and the reaction is stopped;

[0104] Based on the mass percentage of castor oil being 100%, the mass percentage of tetrabutyl titanate is 0.5%;

[0105] (2) The castor oil-modified polyol obtained in step (1) reacts with dicyclohexylmethane diisocyanate, and the reaction temperature is controlled at ≤80 °C. The hydroxyl value of the reaction product, isocyanate group-terminated prepolymer, is measured to be 4.2 mg KOH / g, and the reaction is stopped;

[0106] Among them, the molar ratio of the hydroxyl group in the castor oil-modified polyol to the isocyanate group in dicyclohexylmethane diisocyanate is 1:1.4;

[0107] (3) The isocyanate group-terminated prepolymer obtained in step (2) reacts with an amino coupling agent, and the reaction temperature is controlled at ≤70 °C. The mass percentage of the isocyanate group in the product, castor oil-modified crosslinking agent, is measured to be 0.08%, and the reaction is stopped to obtain the castor oil-modified crosslinking agent;

[0108] Among them, the amino silane coupling agent is composed of N-(β-aminoethyl)-γ-aminopropyltrimethoxysilane and γ-aminopropyltriethoxysilane (KH550) in a molar ratio of 1:1.3;

[0109] The molar ratio of the amino group in the amino coupling agent to the isocyanate group in the isocyanate group-terminated prepolymer is 1.05:1.

[0110] Example 4

[0111] This embodiment provides a castor oil-modified crosslinking agent and a preparation method thereof. The preparation method of the castor oil-modified crosslinking agent is as follows:

[0112] (1) In a protective gas atmosphere, castor oil (8.8 mol), ethylene glycol (2.2 mol), adipic acid (8 mol), phthalic anhydride (2 mol), and tetrabutyl titanate are mixed and reacted at 190 °C. The acid value of the reaction product, castor oil-modified polyol, is measured to be 5 mg KOH / g, and the reaction is stopped;

[0113] Based on the mass percentage of castor oil and ethylene glycol being 100%, the mass percentage of tetrabutyl titanate is 0.4%;

[0114] (2) React the castor oil-modified polyol obtained in step (1) with toluene diisocyanate, control the reaction temperature ≤ 80 °C, measure that the hydroxyl value of the reaction product, the isocyanate group-terminated prepolymer, is 4.5 mg KOH / g, and stop the reaction;

[0115] Among them, the molar ratio of the hydroxyl group in the castor oil-modified polyol to the isocyanate group in toluene diisocyanate is 1:1.5;

[0116] (3) React the isocyanate group-terminated prepolymer obtained in step (2) with an amino coupling agent, control the reaction temperature ≤ 70 °C, measure that the mass percentage content of the isocyanate group in the product, the castor oil-modified crosslinking agent, is 0.07%, and stop the reaction to obtain the castor oil-modified crosslinking agent;

[0117] Among them, the amino silane coupling agent is composed of N-(β-aminoethyl)-γ-aminopropyltrimethoxysilane and γ-aminopropyltriethoxysilane in a molar ratio of 1:1.6;

[0118] The molar ratio of the amino group in the amino coupling agent to the isocyanate group in the isocyanate group-terminated prepolymer is 1.04:1.

[0119] Example 5

[0120] This example provides a castor oil-modified crosslinking agent and its preparation method. The difference from Example 1 is only that:

[0121] The amino silane coupling agent is composed of N-(β-aminoethyl)-γ-aminopropyltrimethoxysilane and γ-aminopropylmethyldiethoxysilane in a molar ratio of 1:2;

[0122] Other conditions are the same as those in Example 1.

[0123] Example 6

[0124] This example provides a castor oil-modified crosslinking agent and its preparation method. The difference from Example 1 is only that:

[0125] The amino silane coupling agent is composed of N-(β-aminoethyl)-γ-aminopropyltrimethoxysilane and γ-aminopropyltriethoxysilane in a molar ratio of 1:0.5;

[0126] Other conditions are the same as those in Example 1.

[0127] Example 7

[0128] This example provides a castor oil-modified crosslinking agent and its preparation method. The difference from Example 1 is only that:

[0129] The amino silane coupling agent is composed of N-(β-aminoethyl)-γ-aminopropyltrimethoxysilane and γ-aminopropyltriethoxysilane in a molar ratio of 1:3;

[0130] Other conditions are the same as those in Example 1.

[0131] Example 8

[0132] This example provides a castor oil-modified crosslinking agent and its preparation method. The difference from Example 1 is only that:

[0133] The amino silane coupling agent is composed of N-(β-aminoethyl)-γ-aminopropyltrimethoxysilane and γ-aminopropyltriethoxysilane at a molar ratio of 1:0.3;

[0134] Other conditions are the same as those in Example 1.

[0135] Example 9

[0136] This example provides a castor oil-modified crosslinking agent and its preparation method. The difference from Example 1 is only that:

[0137] The amino silane coupling agent is composed of N-(β-aminoethyl)-γ-aminopropyltrimethoxysilane and γ-aminopropylmethyldimethoxysilane at a molar ratio of 1:1;

[0138] Other conditions are the same as those in Example 1.

[0139] Example 10

[0140] This example provides a castor oil-modified crosslinking agent and its preparation method. The difference from Example 1 is only that:

[0141] The amino silane coupling agent is composed of γ-aminopropylmethyldiethoxysilane and γ-aminopropyltriethoxysilane at a molar ratio of 1:1;

[0142] Other conditions are the same as those in Example 1.

[0143] Example 11

[0144] This example provides a castor oil-modified crosslinking agent and its preparation method. The difference from Example 1 is only that:

[0145] The amino silane coupling agent is N-(β-aminoethyl)-γ-aminopropyltrimethoxysilane;

[0146] Other conditions are the same as those in Example 1.

[0147] Example 12

[0148] This example provides a castor oil-modified crosslinking agent and its preparation method. The difference from Example 1 is only that:

[0149] The amino silane coupling agent is γ-aminopropyltriethoxysilane;

[0150] Other conditions are the same as those in Example 1.

[0151] Example 13

[0152] This example provides a castor oil modified crosslinking agent and its preparation method. The difference from Example 1 is only that:

[0153] In step (1) of this example, the amount of castor oil used is 8.7 mol, and the amount of 1,3-propanediol used is 2.9 mol;

[0154] Other conditions are the same as those in Example 1.

[0155] Comparative Example 1

[0156] This comparative example provides a castor oil modified crosslinking agent and its preparation method. The difference from Example 1 is only that:

[0157] In step (1) of this comparative example, the amount of castor oil used is 8 mol, and the amount of 1,3-propanediol used is 3.6 mol;

[0158] Other conditions are the same as those in Example 1.

[0159] Comparative Example 2

[0160] This comparative example provides a modified crosslinking agent and its preparation method. The difference from Example 1 is only that:

[0161] In step (1) of this comparative example, the amount of castor oil used is 0 mol, and the amount of 1,3-propanediol used is 11.6 mol;

[0162] Other conditions are the same as those in Example 1.

[0163] Comparative Example 3

[0164] This comparative example provides a castor oil modified crosslinking agent and its preparation method. The difference from Example 1 is only that:

[0165] In this comparative example, step (3) is not carried out, and the isocyanate group-terminated prepolymer obtained in step (2) is used as the modified crosslinking agent;

[0166] Other conditions are the same as those in Example 1.

[0167] Comparative Example 4

[0168] This comparative example provides an acrylate crosslinking agent, and the acrylate crosslinking agent is 1,6-hexanediol diacrylate.

[0169] Application Example 1

[0170] This application example provides a packaging adhesive film and a preparation method thereof. The packaging adhesive film includes a first EVA layer, a POE layer, and a second EVA layer that are stacked in sequence.

[0171] The material of the POE layer includes the castor oil-modified crosslinking agent provided in Example 1 and POE particles (purchased from Dow Chemical, grade PV 8660). Based on the mass percentage of the POE material being 100%, the mass percentage of the castor oil-modified crosslinking agent is 2%.

[0172] The materials of the first EVA layer and the second EVA layer are EVA particles (purchased from Formosa Plastics, grade 7130F).

[0173] The preparation method of the above packaging adhesive film is as follows:

[0174] Place the materials of the first EVA layer, the POE layer, and the second EVA layer in the corresponding barrels respectively, perform three-layer coextrusion and casting at 90 °C to obtain a coextruded adhesive film with a total grammage of 420 g / m 2 , a total thickness of 540 mm, and a three-layer thickness ratio of 1:1:1.

[0175] Perform electron beam irradiation on the coextruded adhesive film, control the line speed at 15 m / min, the beam current at 20 mA, and the total irradiation dose at 25 kGy to obtain the packaging adhesive film.

[0176] Application Examples 2-13, Comparative Application Examples 1-4

[0177] Application Examples 2-13 and Comparative Application Examples 1-4 respectively provide a packaging adhesive film and a preparation method thereof. The difference from Application Example 1 is only that:

[0178] The castor oil-modified crosslinking agent provided in Example 1 in Application Example 1 is sequentially replaced with the castor oil-modified crosslinking agent provided in Examples 2-13 and the crosslinking agents provided in Comparative Examples 1-4.

[0179] Other conditions are the same as those in Application Example 1.

[0180] Characterize the performance of the packaging adhesive films provided by the above application examples and comparative application examples. The specific test methods are as follows:

[0181] Use the packaging adhesive films provided by the above application examples and comparative application examples to prepare laminates for peel testing respectively. The steps are as follows:

[0182] (1) Stack them in the order of glass / packaging adhesive film (two pieces) / backplane, put them into a vacuum press, evacuate and laminate.

[0183] (2) Cut the packaging adhesive film / backplane layer into specimens with a width of (10 ± 0.5) mm every 5 mm along the width direction.

[0184] Referring to GB / T 29848-2018, the peel strength of each laminate was tested before and after PCT48h, and the results are shown in Table 1.

[0185] Bonding strength between the EVA layer and the POE layer: After cutting the prepared EPE film into 5*5 cm film pieces, place them in boiling water at 100 °C for 6 h, then take them out and cool, and observe whether there is delamination or bubbles between layers.

[0186] The specific test results are shown in Table 1.

[0187] Table 1

[0188]

[0189]

[0190] As can be seen from the above, by designing the raw materials for the preparation of the castor oil modified crosslinking agent, using castor oil and coupling agent, and controlling the content of castor oil in the polyol within a specific range, a castor oil modified crosslinking agent with excellent performance was prepared. Using this castor oil modified crosslinking agent as the crosslinking agent between the EVA layer and the POE layer can enhance the bonding strength between the EVA layer and the POE layer, solve the problem of interlayer slippage, and improve the peel strength of the EPE film. The peel strength between the EPE film and glass before PCT48 h is 70-89 N / cm, and the peel strength between the EPE film and glass after PCT48 h is 32-46 N / cm. After cutting the prepared EPE film into 5*5 cm film pieces, place them in boiling water at 100 °C for 6 h, then take them out and cool, and they do not fall off.

[0191] As can be seen from Example 1 and Examples 5-12, by preferably using a combination of N-(β-aminoethyl)-γ-aminopropyltrimethoxysilane (KH572) and γ-aminopropyltriethoxysilane (KH550) as the coupling agent and controlling the molar ratio of the two within a specific range, the comprehensive performance of the castor oil modified crosslinking agent was further optimized and improved. The peel strength between the EPE film prepared in this way and glass before PCT48 h is 85-89 N / cm, and the peel strength between the EPE film and glass after PCT48 h is 42-46 N / cm. After cutting the prepared EPE film into 5*5 cm film pieces, place them in boiling water at 100 °C for 6 h, then take them out and cool, and they do not fall off and there are no bubbles between layers.

[0192] As can be seen from Example 1, Example 13 and Comparative Example 1, by controlling the content of castor oil in the polyol, which is the raw material for preparing the castor oil-modified crosslinking agent, within a specific range, the present invention prepares a castor oil-modified crosslinking agent with excellent performance, and further prepares a packaging adhesive film with excellent performance.

[0193] As can be seen from Comparative Examples 2-3, by designing the raw materials for preparing the castor oil-modified crosslinking agent, the present invention prepares a castor oil-modified crosslinking agent with excellent performance, and further prepares a packaging adhesive film with excellent performance, improving the comprehensive performance of the EPE adhesive film.

[0194] As can be seen from Comparative Example 4, compared with small molecule acrylate crosslinking agents, the castor oil-modified crosslinking agent provided by the present invention has excellent comprehensive performance. Using this castor oil-modified crosslinking agent as the crosslinking agent between the EVA layer and the POE layer can enhance the bonding strength between the EVA layer and the POE layer, solve the problem of interlayer slippage, and improve the peel strength of the EPE adhesive film.

[0195] In summary, by designing the raw materials for preparing the castor oil-modified crosslinking agent, the present invention prepares a castor oil-modified crosslinking agent with excellent performance. Using this castor oil-modified crosslinking agent as the crosslinking agent between the EVA layer and the POE layer, a packaging adhesive film with excellent comprehensive performance is prepared.

[0196] The applicant declares that the present invention uses the above examples to illustrate the detailed process flow of the present invention, but the present invention is not limited to the above detailed process flow, that is, it does not mean that the present invention must rely on the above detailed process flow to be implemented. Those skilled in the art should understand that any improvement to the present invention, the equivalent substitution of each raw material of the product of the present invention, the addition of auxiliary components, and the selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

Claims

1. A castor oil modified crosslinking agent, characterized in that: The raw materials for preparing the castor oil modified crosslinking agent include the following components: Polyols, acidic compounds, diisocyanates, coupling agents; The polyol includes castor oil; Taking the mole percentage of the polyol as 100 mol %, the mole percentage of castor oil in the polyol is ≥ 75 mol %; The acidic compound includes a dibasic acid and / or a dibasic acid anhydride.

2. The castor oil modified crosslinking agent according to claim 1, characterized in that The coupling agent includes an aminosilane coupling agent; The aminosilane coupling agent is selected from any one of γ-aminopropyltriethoxysilane, N-(β-aminoethyl)-γ-aminopropyltrimethoxysilane, 3-aminopropyltrimethoxysilane, N-(β-aminoethyl)-γ-aminopropyltriethoxysilane, γ-aminopropylmethyldiethoxysilane or γ-aminopropylmethyldimethoxysilane, or a combination of at least two thereof.

3. The castor oil modified crosslinking agent according to claim 2, characterized in that The coupling agent includes a combination of N-(β-aminoethyl)-γ-aminopropyltrimethoxysilane and γ-aminopropyltriethoxysilane; The molar ratio of the N-(β-aminoethyl)-γ-aminopropyltrimethoxysilane to γ-aminopropyltriethoxysilane is 1:(0.5-2).

4. The castor oil modified crosslinking agent according to claim 1, characterized in that The polyols also include small molecule diols; The small molecule diol is selected from any one of 1,3-propylene glycol, 1,4-butanediol, ethylene glycol or diethylene glycol, or a combination of at least two thereof.

5. The castor oil modified crosslinking agent according to claim 1, characterized in that The raw materials for preparing the castor oil modified cross-linking agent also include a catalyst; The catalyst includes tetrabutyl titanate and / or tetraisopropyl titanate.

6. A method for preparing a castor oil modified crosslinking agent as claimed in any one of claims 1 to 5, characterized in that: The preparation method comprises the following steps: (1) mixing a polyol, an acidic compound and a catalyst, and reacting them to obtain a castor oil-modified polyol; (2) reacting the castor oil-modified polyol obtained in step (1) with diisocyanate to obtain an isocyanate-terminated prepolymer; (3) reacting the isocyanate-terminated prepolymer obtained in step (2) with a coupling agent to obtain the castor oil-modified crosslinking agent.

7. The preparation method according to claim 6, characterized in that: The molar ratio of the polyol to the acidic compound in step (1) is (1.1-1.2):1; Taking the mass percentage of the polyol in step (1) as 100%, the mass percentage of the catalyst is 0.3-0.8%; The reaction temperature in step (1) is 160-230°C; The acid value of the castor oil modified polyol is ≤5 mgKOH / g; The reaction in step (1) is carried out in a protective gas atmosphere.

8. The preparation method according to claim 6, characterized in that: In step (2), the molar ratio of the hydroxyl group in the castor oil-modified polyol to the isocyanate group in the diisocyanate is 1:(1.3-1.5); The reaction temperature in step (2) is ≤80°C; The hydroxyl value of the isocyanate-terminated prepolymer is ≤5 mgKOH / g.

9. The preparation method according to claim 6, characterized in that: The molar ratio of the amino group in the coupling agent to the isocyanate group in the isocyanate-terminated prepolymer in step (3) is (1-1.05):1; The reaction temperature in step (3) is ≤70°C; Taking the mass percentage of the castor oil modified cross-linking agent obtained after the reaction in step (3) as 100%, the mass percentage of isocyanate groups in the castor oil modified cross-linking agent is ≤0.1%.

10. A packaging film, characterized in that: The encapsulation film comprises a first EVA layer, a POE layer and a second EVA layer which are stacked in sequence; The material of the POE layer includes the castor oil modified crosslinking agent and POE particles as described in any one of claims 1 to 5; Taking the mass percentage of the POE material as 100%, the mass percentage of the castor oil modified crosslinking agent is 1-3%.

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