Method for detecting precipitation of POE (Polyolefin Elastomer) resin particle aid

Abstract

The invention discloses a POE (Polyolefin Elastomer) resin particle assistant precipitation detection method which comprises the following steps: (a) fully mixing POE resin particles with an assistant, and curing to obtain test sample POE particles; taking the EVA particles without addition of the auxiliary agent as test sample EVA particles; (b) respectively carrying out tape casting on the test sample POE particles and the test sample EVA particles under the same tape casting process parameters to obtain a POE adhesive film and an EVA adhesive film; (c) respectively shearing the obtained adhesive films into the same size, respectively adhering a layer of EVA (Ethylene Vinyl Acetate) film to the upper part and the lower part of a layer of POE (Polyolefin Elastomer) film, recording as a sample C, and aging; and (d) a crosslinking degree test is carried out on the POE adhesive film which is not aged after lamination and curing, a crosslinking degree test is carried out on the middle layer POE square sheet of the aged sample C after lamination and curing, and the larger the crosslinking degree difference is, the more serious the precipitation of the auxiliary agent of the POE layer is. The method not only can simply and effectively evaluate the precipitation performance of different assistants, but also can reflect the difference of the precipitation behaviors of the assistants of different POE particles in the EPE adhesive film from the side.

Description

Technical Field

[0001] The invention relates to a method for detecting the precipitation of a POE resin particle auxiliary agent, and belongs to the field of photovoltaic packaging material testing. Background Art

[0002] Additive precipitation refers to the phenomenon that during the processing or use of polymer materials, additives that were originally evenly dispersed in the resin matrix migrate to the surface of the material. This phenomenon may cause a decrease in material performance, such as appearance defects, reduced mechanical properties, degradation of electrical properties, etc. In severe cases, it may even affect the safety and reliability of the product.

[0003] At present, the common encapsulation films for photovoltaic modules mainly include POE (polyolefin elastomer) film, EVA (ethylene-vinyl acetate) film and the three-layer EPE film obtained by compounding the two. The three films each have their own obvious advantages and disadvantages: ① POE film has high volume resistivity and good module anti-PID performance, but due to its non-polar molecular structure, after it is mixed with polar additives for casting, the polar additives are easy to migrate and precipitate to the surface of POE film. Finally, when producing modules, the battery cells on the production line slip, which causes the problem of low module yield; ② EVA film is easy to store, but the film itself is acidic, and the water resistance and volume resistivity of the film are low, and the module anti-PID performance is poor; ③ Although EPE film takes into account the low cost of EVA and the water resistance of POE, as the storage time increases, the polar additives are easy to migrate from the POE layer to the EVA layer, resulting in uneven overall distribution of the additives, affecting the shelf life of the film and the cross-linking degree of the final product. In view of the above situation, the problem of additive precipitation in POE film is crucial to ensure the stability and processability of the material.

[0004] How to judge the precipitation of additives in POE particles, so as to screen out POE resin particles that are not prone to additive precipitation, is of great significance to the formula iteration of POE photovoltaic film and the selection of film raw material resin particles.

[0005] At present, there are few methods on the market to effectively evaluate the precipitation performance of additives in POE resin particles and to measure the precipitation ability of additives in different POE resin particles. Patent CN115343215A evaluates the additive absorption of the film by the friction coefficient after the particles are pressed into sheets. Patent CN117825553A uses gas chromatography to detect the precipitation of additives in the matured particles. This method is costly, not simple and direct, and lacks in-depth thinking on the impact of POE structural characteristics on its additive absorption capacity. The above method is difficult to provide effective selection guidance for resin manufacturers to optimize POE photovoltaic particle products. In view of this, it is necessary to provide an evaluation method for evaluating the precipitation performance of POE additives to provide an effective reference for the selection of formulation additives and resin particles in POE photovoltaic films. Summary of the invention

[0006] The purpose of the present invention is to provide a method for detecting the precipitation of POE resin particle additives. The method is simple and effective, and can detect the precipitation of formulation additives and resin particles in POE photovoltaic adhesive films, providing a reference for selecting suitable resin particles.

[0007] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0008] In order to achieve the above object, the present invention provides a method for detecting the precipitation of POE resin particle additives, comprising the following steps:

[0009] (a) Pre-prepared sample: POE resin particles and additives are fully mixed and matured to obtain test sample POE particles; EVA particles without additives are taken as test sample EVA particles;

[0010] (b) Casting: Under the same casting process parameters, the test sample POE particles are cast to obtain POE films; the test sample EVA particles are cast to obtain EVA films;

[0011] (c) Sample preparation: The obtained film was cut into films of the same size, and the POE film was designated as sample A, and the EVA film was designated as sample B. A layer of EVA film was laminated on the upper and lower sides of the POE film, and designated as sample C, and then aged.

[0012] (d) Testing stage: For the unaged sample A, the cross-linking degree was tested after lamination and curing to obtain the cross-linking degree λ0. For the middle layer POE membrane of the aged sample C, the cross-linking degree was tested after lamination and curing to obtain the cross-linking degree λ1. The greater the difference in cross-linking degree, the more serious the precipitation of the additive in the POE layer.

[0013] Further, the POE resin particles in step (a) are ethylene-α-olefin copolymer POE, wherein the α-olefin includes one or more selected from the group consisting of propylene, 1-butene, 1-pentene, 4-methyl-1-pentene, 1-hexene, 1-heptene, 1-octene, 1-decene, 1-undecene, 1-dodecene, 1-tetradecene, 1-hexadecene and 1-eicosene.

[0014] In particular, this method is based on the study of the polar interaction force between the film matrix resin and the additive. Therefore, a highly polar EVA film is selected to be attached to the surface of the POE film to promote the additive to precipitate from the POE layer and be absorbed by the EVA layer, thereby affecting the cross-linking degree of the product through the change in the amount of additive, so as to evaluate the additive precipitation of the POE layer.

[0015] In some preferred embodiments of the present invention, a certain load or pressure may be applied to the sample C to ensure close adhesion between the layers, and the POE layer additive may migrate to the EVA layer and be further absorbed;

[0016] Furthermore, the auxiliary agent is a peroxide initiator or an acrylate crosslinking agent. Based on 100 parts by weight of the POE resin particles, the weight of the acrylate crosslinking agent is 0.1-5 parts, and the weight of the peroxide initiator is 0.1-5 parts.

[0017] Further, the peroxide initiator is one or more of tert-butyl peroxy isopropyl carbonate, 2,5-dimethyl-2,5-(bis-tert-butylperoxy)hexane, tert-butyl peroxy carbonate-2-ethylhexyl ester, 1,1-bis(tert-butylperoxy)-3,3,5-trimethylcyclohexane, 1,1-bis(tert-amylperoxy)-3,3,5-trimethylcyclohexane, 1,1-bis(tert-amylperoxy)-3,3,5-trimethylcyclohexane, 1,1-bis(tert-amylperoxy)cyclohexane, 1,1-bis(tert-butylperoxy)cyclohexane, 2,2-bis(tert-butylperoxy)butane, tert-butyl peroxy 2-ethylhexyl carbonate, tert-amyl peroxy carbonate, tert-butyl peroxy 3,3,5-trimethylhexanoate, and tert-butyl peroxy-2-ethylhexyl carbonate.

[0018] Further, the acrylate crosslinking agent is one or more of triallyl isocyanurate, trimethylolpropane triacrylate, trimethylolpropane trimethacrylate, pentaerythritol triacrylate, tris(2-hydroxyethyl)isocyanuric acid triacrylate, ethoxylated trimethylolpropane triacrylate, propoxylated trimethylolpropane triacrylate, ethoxylated glycerol triacrylate, propoxylated glycerol triacrylate, pentaerythritol tetraacrylate, ethoxylated pentaerythritol tetraacrylate, trimethylolpropane tetraacrylate, ditrimethylolpropane tetraacrylate, ditrimethylolpropane tetramethacrylate, propoxylated pentaerythritol tetraacrylate, tricyclohexane dimethanol diacrylate, propoxylated neopentyl glycol diacrylate, ethoxylated bisphenol A diacrylate, ethoxylated bisphenol A dimethacrylate, 2-butyl-2-ethyl-1,3-propanediol diacrylate, diethylene glycol dimethacrylate, triethylene glycol dimethacrylate, and polyethylene glycol dimethacrylate.

[0019] Furthermore, in step (a), the aging temperature is 30 to 60° C., preferably 53° C., so that the additive is fully absorbed by the particles, and the aging time is 3 to 5 hours.

[0020] Furthermore, in step (c), natural aging or high temperature aging can be performed. Preferably, natural aging can be performed at room temperature of 20 to 25°C for 5 to 10 days; high temperature aging can be performed at a high temperature of 40 to 55°C for 7 to 12 hours. At the same time, in order to monitor the precipitation process of the additive, sampling tests can be performed at multiple time points during the aging time.

[0021] The positive effects of the present invention are: ① The present invention is simple to prepare samples and easy to operate, and the additive precipitation behavior of POE particles can be intuitively reflected only by the crosslinking degree test; ② At the same time, the sample preparation structure of this method is similar to that of EPE film, which can more intuitively reflect the migration of POE layer additives to EVA layer additives, and has practical significance for the particle selection of downstream film factories. DETAILED DESCRIPTION

[0022] The present invention is further described below by specific examples, which are only used as explanations of the present invention and do not limit the scope of the present invention. In this application, "parts" and "%" are by weight unless otherwise specified.

[0023] Main materials:

[0024] EVA particles: V2825, manufacturer: Sailbon;

[0025] Ethylene-octene copolymer A: 8660, manufacturer: Dow;

[0026] Ethylene-octene copolymer B: 8669, manufacturer: Dow;

[0027] Ethylene-butene copolymer C: LF575, manufacturer: LG;

[0028] Ethylene-butene copolymer D: LF675, manufacturer: LG;

[0029] Ethylene-butene copolymer E: 38680, manufacturer: Dow;

[0030] Ethylene-butene copolymer F: 38688, manufacturer: Dow;

[0031] Ethylene-butene copolymer G: 69057, manufacturer: Wanhua;

[0032] Ethylene-butene copolymer H: 69147, manufacturer: Wanhua;

[0033] Tert-butyl peroxy-2-ethylhexyl carbonate, Aladdin, purity 95%;

[0034] Ethoxylated trimethylolpropane triacrylate, Aladdin, purity 95%;

[0035] Tert-butyl peroxyisopropyl carbonate, Aladdin, purity 95%;

[0036] Triallyl isocyanurate, Aladdin, purity 95%;

[0037] 1,1-Bis(tert-butylperoxy)-3,3,5-trimethylcyclohexane, Acros, purity 95%;

[0038] Trimethylolpropane triacrylate, Acros, purity 95%;

[0039] Test instruments and methods:

[0040] Cross-linking degree: The test method of cross-linking degree refers to the China Photovoltaic Industry Association standard T / CPIA 0006-2017 "Co-olefin Film for Photovoltaic Module Encapsulation". Sample preparation: After taking two pieces of film and stacking them, laminating them with a laminator, weigh 0.5±0.01g, cut them into small particles with a size of less than 3mm×3mm, and prepare 3 samples for each group. After extracting with xylene at 140℃ for 5h, put them in a 140℃ vacuum oven and dry them to constant weight.

[0041] Melt index: measured in accordance with ASTM D-1238 (conditions: 190° C., 2.16 kg load).

[0042] Example 1

[0043] Sample preparation: Ethylene-octene copolymer A was fully mixed with 1% of tert-butyl peroxy-2-ethylhexyl carbonate and 0.5% of ethoxylated trimethylolpropane triacrylate, and then aged in an oven at 53°C for 5 hours to obtain test sample POE particles. EVA particles without adding additives were recorded as test sample EVA particles.

[0044] The test sample POE particles and the test sample EVA particles were respectively added to the extruder for casting, and the POE film and EVA film were prepared through the processes of melt extrusion, film casting, cooling, slitting and winding. Among them, the extrusion temperature of the casting machine is 85°C, the screw speed is 45rpm, the traction speed is 0.7rpm, and the winding speed is 1.2rpm. The obtained film was cut into 5cm·5cm square pieces, respectively, and recorded as POE square piece sample A and EVA square piece sample B. A layer of EVA square piece sample B was attached to the upper and lower layers of a layer of POE square piece sample A, respectively, and recorded as square piece sample C. Sample C was placed in the middle of a 10cm·10cm float glass, and then two 10cm·10cm float glasses were pressed on sample C. Under the same conditions, multiple samples C were prepared at the same time, placed at room temperature of 23°C, aged naturally, and then taken out at different times to test the crosslinking degree. For the sample A that was not aged, the crosslinking degree was tested after lamination and curing to obtain the crosslinking degree λ0. For the middle layer POE square pieces of the sample C taken out at different times after aging, the crosslinking degree was tested after lamination and curing to obtain the crosslinking degree λ1. The sample C was placed at room temperature for natural aging, and the crosslinking degree of the middle layer POE square piece of the sample C was tested after 1 day, 3 days, 5 days, and 7 days. The crosslinking degree test results are shown in Table 1.

[0045] Example 2

[0046] The detection was carried out in the same manner as in Example 1, except that ethylene-octene copolymer B was used instead of ethylene-octene copolymer A.

[0047] Example 3

[0048] The detection was carried out in the same manner as in Example 1, except that ethylene-butene copolymer C was used instead of ethylene-octene copolymer A.

[0049] Example 4

[0050] The detection was carried out in the same manner as in Example 1, except that ethylene-butene copolymer D was used instead of ethylene-octene copolymer A.

[0051] Example 5

[0052] The detection was carried out in the same manner as in Example 1, except that ethylene-butene copolymer E was used instead of ethylene-octene copolymer A, and the auxiliary agents used were changed to 0.9% tert-butyl peroxyisopropyl carbonate and 0.6% triallyl isocyanurate.

[0053] Example 6

[0054] The detection was carried out in the same manner as in Example 1, except that ethylene-butene copolymer F was used instead of ethylene-octene copolymer A, and the auxiliary agents used were changed to 0.9% tert-butyl peroxyisopropyl carbonate and 0.6% triallyl isocyanurate.

[0055] Example 7

[0056] The detection was carried out in the same manner as in Example 1, except that ethylene-butene copolymer G was used instead of ethylene-octene copolymer A, and the auxiliary agents used were changed to 1% tert-butyl peroxy-2-ethylhexyl carbonate and 1% triallyl isocyanurate.

[0057] Example 8

[0058] The detection was carried out in the same manner as in Example 1, except that ethylene-octene copolymer H was used instead of ethylene-octene copolymer A, and the auxiliary agent used was changed to 1% 1,1-bis(tert-butylperoxy)-3,3,5-trimethylcyclohexane and 1% trimethylolpropane triacrylate.

[0059] The melt index of the POE resin particles of the present application was tested, and the test results are shown in Table 1

[0060] Table 1

[0061]

[0062] From the comparison of the performance test data of the embodiments described in the above table, it can be seen that:

[0063] It can be seen from the examples that the method described in the present invention can be used to compare the crosslinking degree changes between different particles. As shown in Examples 1 and 2, after 7 days, the crosslinking degree of Example 1 decreased from 88.1% in the initial state to 72.6%. The crosslinking degree of Example 2 decreased from 82.9% in the initial state to 54.4%, and the change in crosslinking degree was more obvious. The greater the difference in crosslinking degree, the more serious the precipitation of the additive, that is, the precipitation of the additive in Example 2 was more serious than that in Example 1. Therefore, for upstream resin manufacturers, developing POE particles with low crosslinking degree changes will help improve the precipitation of additives in the film in actual use by downstream film manufacturers.

[0064] On the other hand, by comparing Examples 1 and 2, Examples 3 and 4, Examples 5 and 6, and Examples 7 and 8, it can be found that for POE of the same copolymer type monomer, the precipitation of additives in high melt index products is more obvious than that in low melt index products, that is, when samples are prepared under the same formula and aged under the same conditions, the degree of crosslinking decays more obviously. It can be seen that by evaluating the precipitation of additives of POE particles through the method of the present invention, the precipitation behavior of additives of POE particles of different manufacturers and brands can be further evaluated based on the physical properties of the particle structure, which is also beneficial for the application development research of upstream particle manufacturers.

[0065] The above is only a preferred embodiment of the present invention. It should be pointed out that ordinary technicians in this field can make several improvements and supplements without departing from the method of the present invention. These improvements and supplements should also be regarded as the scope of protection of the present invention.

Claims

1. A method for detecting the precipitation of POE resin particle additives, characterized in that: The steps include: (a) Pre-prepared sample: POE resin particles and additives are fully mixed and matured to obtain test sample POE particles; EVA particles without additives are taken as test sample EVA particles; (b) Casting: Under the same casting process parameters, the test sample POE particles are cast to obtain POE films; the test sample EVA particles are cast to obtain EVA films; (c) Sample preparation: The obtained adhesive film is cut into films of the same size, the POE film is referred to as sample A, the EVA film is referred to as sample B, and a layer of EVA film is laminated on the upper and lower sides of the POE film, respectively, referred to as sample C, and then aged; (d) Testing stage: For the unaged sample A, the cross-linking degree was tested after lamination and curing to obtain the cross-linking degree λ0. For the middle layer POE membrane of the aged sample C, the cross-linking degree was tested after lamination and curing to obtain the cross-linking degree λ1. The greater the difference in cross-linking degree, the more serious the precipitation of the additive in the POE layer.

2. The detection method according to claim 1, characterized in that: The POE resin particles in step (a) are ethylene-α-olefin copolymer POE, wherein the α-olefin includes one or more selected from propylene, 1-butene, 1-pentene, 4-methyl-1-pentene, 1-hexene, 1-heptene, 1-octene, 1-decene, 1-undecene, 1-dodecene, 1-tetradecene, 1-hexadecene and 1-eicosene.

3. The detection method according to any one of claims 1 to 2, characterized in that: The auxiliary agent is a peroxide initiator or an acrylate crosslinking agent.

4. The detection method according to claim 3, characterized in that: Based on 100 parts by weight of the POE resin particles, the amount of the acrylate crosslinking agent added is 0.1-5 parts, and the amount of the peroxide initiator added is 0.1-5 parts.

5. The detection method according to any one of claims 1 to 4, characterized in that: The peroxide initiator is one or more of tert-butyl peroxy isopropyl carbonate, 2,5-dimethyl-2,5-(bis-tert-butylperoxy)hexane, tert-butyl peroxy carbonate-2-ethylhexyl ester, 1,1-bis(tert-butylperoxy)-3,3,5-trimethylcyclohexane, 1,1-bis(tert-amylperoxy)-3,3,5-trimethylcyclohexane, 1,1-bis(tert-amylperoxy)-3,3,5-trimethylcyclohexane, 1,1-bis(tert-amylperoxy)cyclohexane, 1,1-bis(tert-butylperoxy)cyclohexane, 2,2-bis(tert-butylperoxy)butane, tert-butyl peroxy 2-ethylhexyl carbonate, tert-amyl peroxy carbonate, tert-butyl peroxy 3,3,5-trimethylhexanoate, and tert-butyl peroxy-2-ethylhexyl carbonate; Preferably, the acrylate crosslinking agent is one or more of triallyl isocyanurate, trimethylolpropane triacrylate, trimethylolpropane trimethacrylate, pentaerythritol triacrylate, tris(2-hydroxyethyl)isocyanuric acid triacrylate, ethoxylated trimethylolpropane triacrylate, propoxylated trimethylolpropane triacrylate, ethoxylated glycerol triacrylate, propoxylated glycerol triacrylate, pentaerythritol tetraacrylate, ethoxylated pentaerythritol tetraacrylate, trimethylolpropane tetraacrylate, ditrimethylolpropane tetraacrylate, ditrimethylolpropane tetramethacrylate, propoxylated pentaerythritol tetraacrylate, tricyclohexane dimethanol diacrylate, propoxylated neopentyl glycol diacrylate, ethoxylated bisphenol A diacrylate, ethoxylated bisphenol A dimethacrylate, 2-butyl-2-ethyl-1,3-propanediol diacrylate, diethylene glycol dimethacrylate, triethylene glycol dimethacrylate, and polyethylene glycol dimethacrylate.

6. The detection method according to any one of claims 1 to 5, characterized in that: In step (a), the aging temperature is 30 to 60° C., preferably 53° C., and the aging time is 3 to 5 hours.

7. The detection method according to any one of claims 1 to 6, characterized in that: A load or pressure is applied to the sample C to make the layers fit closely together.

8. The detection method according to any one of claims 1 to 6, characterized in that: In step (c), natural aging or high temperature aging is performed.

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