Acrylic resin for water-blocking film and preparation method thereof

Abstract

The invention relates to the technical field of polyester resin, in particular to acrylic resin for a water-blocking film and a preparation method of the acrylic resin. The acrylic resin is a (styrene-acrylonitrile)-b-(flexible acrylic acid-functional monomer)-c-(styrene-acrylonitrile-silane coupling agent) segmented polymer; the segmented polymer is composed of the following components in parts by mass: 20-70 parts of flexible acrylic monomer; 5 to 25 parts of acrylonitrile; 20 to 50 parts of styrene; 1-7 parts of a silane coupling agent; 2-10 parts of a functional monomer, wherein the functional monomer is used for carrying out a cross-linking reaction with the curing agent; the (styrene-acrylonitrile)-b-(flexible acrylic acid-functional monomer)-c-(styrene-acrylonitrile-silane coupling agent) three-stage polymer prepared in the invention has good heat resistance and certain elasticity, is acrylic resin with good binding force with a water-blocking coating, and is used for a polymer protection layer.

Description

Technical Field

[0001] The present invention relates to the technical field of polyester resins, and in particular to an acrylic resin for a water-blocking film and a preparation method thereof. Background Art

[0002] Currently, the problem of water-blocking of film materials has become a research hotspot in the industrial field and has increasingly wide applications. For example, in quantum dot display screens, OLED display devices, photovoltaic water-blocking backplates, photovoltaic front plates, etc. Generally, the method is to deposit an inorganic oxide layer on a substrate such as PET by magnetron sputtering or evaporation to reduce the water vapor transmission rate. However, after damp heat aging, the water vapor transmission rate generally increases rapidly. Summary of the Invention

[0003] The purpose of the present invention is to overcome the deficiencies in the prior art and provide an acrylic resin for a water-blocking film and a preparation method thereof.

[0004] To solve the above technical problems, the technical solution adopted by the present invention is as follows: An acrylic resin for a water-blocking film, wherein the acrylic resin is a segmented polymer of (styrene-acrylonitrile)-b-(flexible acrylic-functional monomer)-c-(styrene-acrylonitrile-silane coupling agent).

[0005] Furthermore, the mass parts composition of each component in the segmented polymer is as follows: 20-70 parts of flexible acrylic monomer; 5-25 parts of acrylonitrile; 20-50 parts of styrene; 1-7 parts of silane coupling agent; 0.5 part of chain transfer agent; 2-10 parts of functional monomer, and the functional monomer is used to crosslink with a curing agent.

[0006] Furthermore, the flexible acrylic monomer includes one of methyl acrylate, ethyl acrylate, (n / i)-acrylate, (n / i / t)-butyl acrylate, amyl acrylate, cyclohexyl acrylate, and butyl methacrylate, and the TG of its homopolymer is 8-55°C.

[0007] Furthermore, the silane coupling agent is a vinyl silane coupling agent, and the silane coupling agent is selected from KH570 or KH171; the chain transfer agent is selected from one or a combination of heptanitrile dithiobenzoate and 2,4-diphenyl-4-methyl-1-pentene.

[0008] Furthermore, the functional monomer is selected from one of acrylic acid, (meth)acrylic acid, and (meth)acrylic acid hydroxyalkyl ester.

[0009] Further, the initiator is selected from one of azobisisobutyronitrile or benzoyl peroxide.

[0010] Further, the content of the flexible acrylic monomer in segment B is preferably 40-70%. Further, the ratio of segments A, B, and C is 13-28:41-73:14-31 respectively.

[0011] A preparation method of an acrylic resin for a water-blocking film, the preparation method comprising the following steps: Polymerize a mixture S1 of a certain amount of ethyl acetate, styrene, acrylonitrile, initiator azobisisobutyronitrile, and chain transfer agent at temperature T °C for T1 hours, add a mixture S2 of ethyl acetate, flexible acrylic monomer, acrylic acid, and initiator azobisisobutyronitrile, and react for T2 hours. Finally, add a mixture S3 of ethyl acetate, styrene, acrylonitrile, KH570, and initiator azobisisobutyronitrile and react for T1 hours.

[0012] Further, the polymerization temperature of the mixture S1 is 75-85 °C, the polymerization time T1 is 4-5 hours, and T2 is 4-5 hours.

[0013] Further, in the preparation method, S1 + S2 + S3 = 200.3 parts, S3 = S1 + S KH570 , with a total of 1 part of KH570, 3 parts of acrylic acid, X parts of acrylonitrile, 0.3 parts of azobisisobutyronitrile, and 100 parts of ethyl acetate as the solvent.

[0014] The beneficial effects of adopting the technical solution of the present invention are: In the present invention, the addition of the flexible acrylic monomer makes the resin elastic and can well eliminate thermal stress. Among them, butyl methacrylate (27 °C), tert-butyl acrylate (55 °C), cyclohexyl acrylate (16 °C), and methyl acrylate (8 °C) have better effects, and it is advisable to select the homopolymer with a TG of 8-55 °C. At the same time, it can be seen from the comparative examples that the method of polymerizing the three-segment ABC makes the polymer have higher tensile strength and elongation at break, can better release the thermal stress during aging, and has a lower water vapor transmission rate.

[0015] The three-segment polymer (styrene-acrylonitrile)-b-(flexible acrylic-functional monomer)-c-(styrene-acrylonitrile-silane coupling agent) prepared in the present invention has good heat resistance, certain elasticity, and good adhesion to the water-blocking coating, and is an acrylic resin used for a polymer protective layer. Specific Embodiments

[0016] The present invention will be further described below in conjunction with specific embodiments and the specification.

[0017] The acrylic resin for the water-blocking film in the present invention example is specifically a (styrene-acrylonitrile)-b-(flexible acrylic-functional monomer)-c-(styrene-acrylonitrile-silane coupling agent) segmented polymer.

[0018] Furthermore, the mass fraction composition of each component in the segmented polymer is as follows: 20-70 parts of flexible acrylic monomer; 5-25 parts of acrylonitrile, and acrylonitrile plays a role in heat resistance; 20-50 parts of styrene, and styrene is used to improve toughness; 1-7 parts of silane coupling agent, which acts by combining with metal oxides in the water-blocking coating; 2-10 parts of functional monomer, and the functional monomer is used to carry out a crosslinking reaction with a curing agent, and the functional monomer is selected from one of acrylic acid, (meth)acrylic acid, and (meth)acrylic acid hydroxyalkyl ester; 0.1-0.4 parts of initiator.

[0019] Specifically, the flexible acrylic monomer includes one of methyl acrylate, ethyl acrylate, (n- / iso-)acrylate, (n- / iso- / tert-)butyl acrylate, amyl acrylate, cyclohexyl acrylate, and butyl methacrylate, and the TG of its homopolymer is 8-55 °C.

[0020] Specifically, the silane coupling agent is a vinyl silane coupling agent.

[0021] Specifically, the silane coupling agent is selected from KH570 or KH171.

[0022] Specifically, the initiator is selected from one of azobisisobutyronitrile or benzoyl peroxide.

[0023] Specifically, it is appropriate that the flexible acrylic monomer accounts for 40-70%, and the ABC three segments are 13-28:41-73:14-31 for the ABC three segments respectively.

[0024] The preparation method of the acrylic resin for the water-blocking film in the present invention includes the following steps: Polymerize a mixture S1 of a certain amount of solvent ethyl acetate, styrene, acrylonitrile, and initiator azobisisobutyronitrile at a temperature of T °C for T1 hours, add a mixture S2 of solvent ethyl acetate, flexible acrylic monomer, acrylic acid, and initiator azobisisobutyronitrile, and react for T2 hours, and finally add a mixture S3 of solvent ethyl acetate, styrene, acrylonitrile, KH570, and initiator azobisisobutyronitrile and react for T1 hours.

[0025] Specifically, the polymerization temperature of the mixture S1 is 75-85 °C, the polymerization time T1 is 4-5 hours, and T2 is 4-5 hours.

[0026] Specifically, in the preparation method, S1 + S2 + S3 = 200.3 parts, and S3 = S1 + S KH570 , with a total of 1 part of KH570, 3 parts of acrylic acid, X parts of acrylonitrile, 0.3 parts of azobisisobutyronitrile, and 100 parts of solvent ethyl acetate.

[0027] Specifically, the initiator is selected from one of azobisisobutyronitrile or benzoyl peroxide.

[0028] Example 1: A mixture of a certain amount of solvent ethyl acetate, styrene, acrylonitrile, initiator azobisisobutyronitrile, and chain transfer agent S1 was polymerized at a temperature of T (°C) for T1 hours. Then, a mixture of solvent ethyl acetate, flexible acrylic monomer, acrylic acid, and initiator azobisisobutyronitrile S2 was added and reacted for T2 hours. Finally, a mixture of solvent ethyl acetate, styrene, acrylonitrile, KH570, and initiator azobisisobutyronitrile S3 was added and reacted for T1 hours. Among them, S1 + S2 + S3 = 200.3 parts, S3 = S1 + SKH570, where KH570 is 1 part, acrylic acid is 3 parts, acrylonitrile is X parts, azobisisobutyronitrile is 0.3 parts, the addition amount of chain transfer agent 2,4-diphenyl-4-methyl-1-pentene is 0.5 parts, and the solvent ethyl acetate is 100 parts.

[0029] 100 parts of the obtained acrylic resin was mixed with 5 parts of commercially available Bayer L-75 curing agent, coated on the water-blocking coating layer, with a dry thickness of 1 μm, and cured at 12°C for 10 minutes. The water vapor transmission rates Z (g / m 2 .day) of the initial and double 85 aging of the water-blocking film were tested. Among them, the initial water vapor transmission rate was 0.05 (g / m 2 .day), and the water vapor transmission rate of the water-blocking adhesive film without applying the polymer protective layer after double 85 aging was tested to be 0.46 (g / m 2 .day). The test method was: After aging at 85°C and 85% RH for 500H, the water vapor transmission rate was tested under the conditions of 38°C and 90% RH.

[0030] Comparative Example 1 was to uniformly add the monomers, solvent ethyl acetate, and azobisisobutyronitrile, and react for 2T1 + T2 hours to obtain the acrylic resin. Comparative Example 2 was to add KH570 in the S1 stage, and Comparative Example 3 was to add KH570 in the S3 stage.

[0031] The addition amounts of specific raw materials and performance tests are shown in Table 1 Table 1 The test standards for tensile strength and elongation at break are GB / T 1040.3 - 2006.

[0032] As can be seen from Table 1, the addition of flexible acrylic monomers endows the resin with elasticity and enables it to effectively eliminate thermal stress. Among them, butyl methacrylate (27 °C), tert-butyl acrylate (55 °C), cyclohexyl acrylate (16 °C), and methyl acrylate (8 °C) show good effects. It is advisable to select the homopolymer with a TG of 8 - 55 °C. At the same time, it can be seen from the comparative examples that the ABC three-segment polymerization method endows the polymer with higher tensile strength and elongation at break, enabling it to better release the thermal stress during aging and having a lower water vapor transmission rate. Comparing Example 2 and Comparative Example 3, since KH570 is added in advance, more time is available for the silane to crosslink in the presence of trace water, resulting in a decrease in its elongation at break and a slight impact on the water vapor transmission rate. Considering the reaction time and temperature, 75 °C - 85 °C is appropriate. At 90 °C, the reaction is intense, with an increase in radical disproportionation reaction and a decrease in resin elasticity. At 70 °C, the reaction is incomplete. In terms of time, 4 - 5 hours for each segment is appropriate. If the time is too short, the reaction is incomplete and it is not a complete segmented polymerization. If the time is too long, the disproportionation reaction increases and the elasticity decreases slightly. At the same time, acrylonitrile has good heat resistance and can enhance the effect of eliminating thermal stress in the water-blocking coating. However, excessive addition will make the resin brittle, and 10 - 20 parts is advisable. The flexible acrylic monomer is preferably 40 - 70%, and the ABC three segments are 13 - 28:43 - 73:14 - 29 respectively.

[0033] Example 2: A mixture of a certain amount of solvent ethyl acetate, styrene, acrylonitrile, initiator azobisisobutyronitrile, and chain transfer agent S1 was polymerized at 80 (°C) for 4 hours. Then, a mixture of solvent ethyl acetate, flexible acrylic monomer, acrylic acid, and 2-hydroxyethyl acrylate:initiator azobisisobutyronitrile S2 was added and reacted for 4 hours. Finally, a mixture of solvent ethyl acetate, styrene, acrylonitrile, silane coupling agent, and initiator azobisisobutyronitrile S3 was added and reacted for 4 hours to obtain an acrylic resin. Among them, S1 + S2 + S3 = 200.3 parts, and S2 = S1 + S 硅烷偶联剂 , and in total, azobisisobutyronitrile:solvent ethyl acetate:butyl methacrylate:styrene:acrylonitrile:silane coupling agent:acrylic acid:2-hydroxyethyl acrylate = 0.3:100:(50 - X1 - X3):(40 - X2):10:X1:X2:X3. The addition amount of chain transfer agent 2,4-diphenyl-4-methyl-1-pentene is 0.5 parts.

[0034] 100 parts of the obtained acrylic resin was mixed with 5 parts of commercially available Bayer L-75 curing agent, coated on the water-blocking coating, with a dry thickness of 1 μm, and cured at 12 °C for 10 minutes. The initial and double 85 aging water vapor transmission rates Z (g / m 2 .day) of the water-blocking film were measured. The initial water vapor transmission rate was 0.05 (g / m 2. day), the water vapor transmission rate of the water-blocking adhesive film without applying the polymer protective layer was 0.46 (g / m 2 . day). After aging at 85°C and 85% RH for 500 h, the water vapor transmission rate was tested under the conditions of 38°C and 90% RH.

[0035] Table 2 As can be seen from Table 2, KH570 can reduce the water vapor transmission rate after hygrothermal aging. The reason is that the silane coupling agent can combine with the water-blocking coating to prevent the water-blocking coating from cracking. At the same time, the silane coupling agent can consume a part of the permeated water. However, when the silane coupling agent KH570 reaches 10 parts, it cannot be coated on the water-blocking coating because during the polymerization process, the siloxane bond of the silane coupling agent will crosslink in the presence of trace amounts of water. When there are 10 parts of KH570, the acrylic resin crosslinks into a jelly-like state and cannot be used further. At the same time, KH171 and KH151 also have the performance of reducing the water vapor transmission rate, but due to the shorter chain, they cannot combine better with the water-blocking coating, so the effect is slightly worse. Since the isocyanate curing agent can crosslink with carboxyl and hydroxyl groups, the molecular weight of the acrylic coating after the reaction is larger, which can better protect the polymer coating. Therefore, both acrylic acid and 2-hydroxyethyl acrylate can reduce the water vapor transmission rate and coordinate with each other to achieve a better effect. However, after adding 5 parts of each, the water vapor transmission rate increases because excessive crosslinking makes the polymer protective layer hard and brittle, without elasticity, and the ability to eliminate thermal stress decreases.

[0036] Example 3 RAFT 1 Heptanenitrile dithiobenzoate A mixture of a certain amount of solvent ethyl acetate, styrene, acrylonitrile, initiator azobisisobutyronitrile, and chain transfer agent S1 was polymerized at 80 (°C) for 4 h. A mixture of solvent ethyl acetate, flexible acrylic monomer, acrylic acid, 2-hydroxyethyl acrylate: initiator azobisisobutyronitrile S2 was added and reacted for 4 h. Finally, a mixture of solvent ethyl acetate, styrene, acrylonitrile, silane coupling agent, and initiator azobisisobutyronitrile S3 was added and reacted for 4 h to obtain an acrylic resin. Among them, azobisisobutyronitrile: solvent ethyl acetate: butyl methacrylate: styrene: acrylonitrile: silane coupling agent: acrylic acid: 2-hydroxyethyl acrylate = 0.3: 100: 44: 37: 10: 3: 3: 3 The adhesive without chain transfer agent cannot form segmented polymers, so it has very poor elasticity and water resistance. The tensile property and water resistance of the adhesive with chain transfer agent are greatly improved. Among them, RAFT1 is the best, AMSD is the second, and dodecyl mercaptan is relatively poor. When RAFT1 and AMSD are used in combination, the best equivalent ratio is 4 / 1 because the transfer temperatures and other conditions of different chain transfer agents are slightly different and can complement each other.

[0037] For those skilled in the art, it is obvious that the present invention is not limited to the details of the above exemplary embodiments, and the present invention can be implemented in other specific forms without departing from the spirit and basic characteristics of the present invention. Therefore, from any point of view, the embodiments should be regarded as exemplary and non-restrictive. The scope of the present invention is defined by the appended claims rather than the above description. Therefore, all changes falling within the meaning and scope of the equivalent elements of the claims are intended to be embraced within the present invention.

[0038] In addition, it should be understood that although this specification is described according to embodiments, not every embodiment only contains an independent claim solution. This narrative way of the specification is only for clarity. Those skilled in the art should regard the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. An acrylic resin for a water-blocking film, characterized in that: The acrylic resin is a segmented polymer of (styrene-acrylonitrile)-b-(flexible acrylic acid-functional monomer)-c-(styrene-acrylonitrile-silane coupling agent).

2. The acrylic resin for a water-blocking film according to claim 1, characterized in that: The mass fractions of each component in the segmented polymer are as follows: 20-70 parts of flexible acrylic monomer; Acrylonitrile 5-25 parts; 20-50 parts of styrene; Silane coupling agent 1-7 parts; Chain transfer agent 0.1-1.0 part; 2-10 parts of functional monomers, wherein the functional monomers are used for cross-linking reaction with curing agents.

3. The acrylic resin for a water-blocking film according to claim 2, characterized in that: The flexible acrylic monomer includes one of methyl acrylate, ethyl acrylate, (n / iso) acrylate, (n / iso / tert) butyl acrylate, pentyl acrylate, cyclohexyl acrylate and butyl methacrylate, and the homopolymer TG thereof is 8-55°C.

4. The acrylic resin for a water-blocking film according to claim 2, characterized in that: The silane coupling agent is a vinyl silane coupling agent, and the silane coupling agent is selected from KH570 or KH171; The chain transfer agent is selected from one or a combination of dithiobenzoic acid heptanoic acid ester and 2,4-diphenyl-4-methyl-1-pentene.

5. The acrylic resin for water-blocking film according to claim 4, characterized in that: The functional monomer is selected from one of acrylic acid, (meth)acrylic acid, and hydroxyalkyl (meth)acrylate.

6. The acrylic resin for water-blocking film according to claim 2, characterized in that: The flexible acrylic monomer is preferably 40-70%, and the three segments ABC are 13-28:43-73:14-29 respectively.

7. A method for preparing an acrylic resin for a water-blocking film, characterized in that: The preparation method comprises the following steps: A mixture S1 of a certain amount of solvent ethyl acetate, styrene, acrylonitrile, initiator azobisisobutyronitrile, and chain transfer agent is polymerized at temperature T°C for T1 hour, a mixture S2 of solvent ethyl acetate, flexible acrylic monomer, acrylic acid, initiator azobisisobutyronitrile is added and reacted for T2 hours, and finally a mixture S3 of solvent ethyl acetate, styrene, acrylonitrile, KH570, initiator azobisisobutyronitrile is added and reacted for T1 hour.

8. The method for preparing an acrylic resin for a water-blocking film according to claim 7, characterized in that: The polymerization temperature of the mixture S1 is 75-85° C., the polymerization time T1 is 4-5 hours, and T2 is 4-5 hours.

9. The method for preparing an acrylic resin for a water-blocking film according to claim 7, characterized in that: In the preparation method, S1+S2+S3=200.3 parts, S3=S1+S KH570 , a total of 1 part of KH570, 3 parts of acrylic acid, X parts of acrylonitrile, 0.3 parts of azobisisobutyronitrile, and 100 parts of solvent ethyl acetate.

10. The acrylic resin for water-blocking film according to claim 7, characterized in that: The initiator is selected from azobisisobutyronitrile or benzoyl peroxide.

Images