A modified C5 petroleum resin, its preparation method, and a pressure-sensitive adhesive composition thereof.

Abstract

This invention relates to the field of pressure-sensitive adhesive materials, and particularly to a modified C5 petroleum resin, its preparation method, and a pressure-sensitive adhesive composition. The preparation method includes the following steps: mixing molten C5 petroleum resin, a polar modifier, and a functional monomer, and carrying out a first reaction to obtain an intermediate product; mixing the intermediate product with an initiator and carrying out a second reaction to obtain the modified C5 petroleum resin. This invention achieves stable control of the solubility parameters of the modified C5 petroleum resin through the synergistic effect of the polar modifier and the functional monomer, combined with precise control of the initiator, significantly reducing the difference in solubility parameters between the modified C5 petroleum resin and APSA, thereby greatly improving its compatibility with APSA. When the modified C5 petroleum resin prepared by the above method is compounded with APSA and a crosslinking agent, the overall performance of the pressure-sensitive adhesive is synergistically optimized.

Description

Technical Field

[0001] This invention relates to the field of pressure-sensitive adhesive materials, and in particular to a modified C5 petroleum resin, its preparation method, and a pressure-sensitive adhesive composition. Background Technology

[0002] Acrylic pressure-sensitive adhesives (APSAs) are widely used in packaging, medical, and electronic component bonding due to their excellent adhesion and weather resistance. To meet diverse application requirements, tackifying resins are often added to APSAs to further enhance their adhesion. C5 petroleum resin is considered an ideal tackifying resin choice due to its low cost, wide availability, and stable quality. However, APSA, as a highly polar polymer system, differs fundamentally from the low polarity of traditional C5 petroleum resin, resulting in poor compatibility. This compatibility issue not only limits the full realization of the tackifying effect but may even lead to a decline in the overall performance of the pressure-sensitive adhesive due to phase separation.

[0003] To overcome the aforementioned compatibility barriers, existing technologies have developed methods for polar modification of C5 petroleum resins. While these methods improve resin polarity to some extent, they still have significant shortcomings: firstly, the modification process often lacks precise control, resulting in limited improvement in compatibility; secondly, they fail to adequately address the challenge of balancing mechanical properties after the addition of tackifying resins—that is, while improving initial tack strength and peel strength, they often inevitably cause a significant decrease in holding power. Summary of the Invention

[0004] The purpose of this invention is to address the problems of poor compatibility and insufficient performance balance of pressure-sensitive adhesive compositions in existing technologies by providing a modified C5 petroleum resin, its preparation method, and a pressure-sensitive adhesive composition. Through the synergistic effect of polar modifiers and functional monomers, combined with precise control of initiators, the solubility parameters of the modified C5 petroleum resin are stably regulated, significantly reducing the difference in solubility parameters between it and APSA, thereby greatly improving its compatibility with APSA and ultimately achieving synergistic optimization of the overall performance of the pressure-sensitive adhesive composition.

[0005] To achieve the above objectives, the present invention provides a method for preparing modified C5 petroleum resin, comprising the following steps:

[0006] S1. Molten C5 petroleum resin, polar modifier and functional monomer are mixed and subjected to the first reaction to obtain intermediate product;

[0007] S2. Mix the intermediate product and the initiator to carry out a second reaction, and obtain the modified C5 petroleum resin.

[0008] Preferably, in S1, the method for preparing molten C5 petroleum resin includes: heating C5 petroleum resin to obtain molten C5 petroleum resin;

[0009] The heating temperature is 120-130℃.

[0010] Preferably, in S1, the polar modifier includes maleic anhydride, and the functional monomer includes acrylic acid;

[0011] The mass ratio of molten C5 petroleum resin, polar modifier and functional monomer is 100:(6-9):(2-4).

[0012] Preferably, in S1, the temperature of the first reaction is 165-175℃ and the time is 1.5-2.5h.

[0013] Preferably, in S2, the initiator includes di-tert-butyl peroxide;

[0014] The mass ratio of molten C5 petroleum resin to initiator is 100:(0.5-1.5).

[0015] Preferably, in S2, the temperature of the second reaction is 150-160℃ and the time is 1-2h.

[0016] The present invention also provides a modified C5 petroleum resin, which is prepared according to the preparation method of the modified C5 petroleum resin.

[0017] The present invention also provides an acrylic pressure-sensitive adhesive composition comprising the following components in parts by weight:

[0018] 100 parts acrylic pressure-sensitive adhesive, 15-25 parts modified C5 petroleum resin, and 0.1-0.5 parts crosslinking agent.

[0019] Preferably, the acrylate pressure-sensitive adhesive is obtained by copolymerizing isooctyl acrylate, butyl acrylate, vinyl acetate and acrylic acid; the mass ratio of isooctyl acrylate, butyl acrylate, vinyl acetate and acrylic acid is (70-80):(5-15):(2-8):(5-15).

[0020] Preferably, the crosslinking agent includes aluminum acetylacetonate.

[0021] The beneficial effects of this invention are as follows:

[0022] This invention provides a method for preparing modified C5 petroleum resin, comprising the following steps: mixing molten C5 petroleum resin, a polar modifier, and a functional monomer to carry out a first reaction, obtaining an intermediate product; mixing the intermediate product with an initiator to carry out a second reaction, obtaining modified C5 petroleum resin. This invention employs a two-step modification process. The first step involves mixing and reacting the molten C5 petroleum resin, polar modifier, and functional monomer to achieve sufficient pre-dispersion and initial grafting of the polar modifier and functional monomer in the resin, laying a homogeneous foundation for subsequent reactions. The second step introduces an initiator for deep reaction, and the precise control of the reaction degree through the initiator significantly improves the modification efficiency and the uniformity of the resin structure. This method, through the synergistic effect of the polar modifier (increasing polarity) and the functional monomer (assisting in regulating reactivity and polarity distribution), combined with precise control of the initiator, achieves stable control of the solubility parameters of the modified C5 petroleum resin, significantly reducing the difference in solubility parameters between it and APSA, thereby greatly improving its compatibility with APSA.

[0023] When the modified C5 petroleum resin prepared by the above method is compounded with APSA and a crosslinking agent, on the one hand, the tackifying effect of the modified resin and the tackiness of APSA work synergistically to significantly improve the initial tack strength and peel strength of the pressure-sensitive adhesive; on the other hand, the crosslinking agent reacts with the polar groups in APSA and the modified resin to form a dynamic crosslinking network, which enhances the cohesion of the system, effectively inhibits the molecular chain creep caused by the addition of tackifying resin, and significantly alleviates the contradiction of "improved initial tack strength and peel strength accompanied by a significant decrease in tackiness" in traditional tackifying systems, thus achieving synergistic optimization of the overall performance of the pressure-sensitive adhesive. Detailed Implementation

[0024] This invention provides a method for preparing modified C5 petroleum resin, comprising the following steps:

[0025] S1. Molten C5 petroleum resin, polar modifier and functional monomer are mixed and subjected to the first reaction to obtain intermediate product;

[0026] S2. Mix the intermediate product and the initiator to carry out a second reaction, and obtain the modified C5 petroleum resin.

[0027] In this invention, in S1, the method for preparing molten C5 petroleum resin includes: heating C5 petroleum resin to obtain molten C5 petroleum resin.

[0028] In this invention, the heating temperature is 120-130℃.

[0029] In this invention, in S1, the polar modifier includes maleic anhydride, and the functional monomer includes acrylic acid.

[0030] In this invention, the mass ratio of molten C5 petroleum resin, polar modifier and functional monomer is 100:(6-9):(2-4).

[0031] In this invention, in S1, the temperature of the first reaction is 165-175°C and the time is 1.5-2.5h.

[0032] In this invention, in S2, the initiator includes di-tert-butyl peroxide.

[0033] In this invention, the mass ratio of molten C5 petroleum resin to initiator is 100:(0.5-1.5).

[0034] In this invention, in S2, the temperature of the second reaction is 150-160°C and the time is 1-2 hours.

[0035] In this invention, in step S2, after the second reaction is completed, the mixture is naturally cooled to room temperature to obtain modified C5 petroleum resin.

[0036] The present invention also provides a modified C5 petroleum resin, which is prepared according to the preparation method of the modified C5 petroleum resin.

[0037] The present invention also provides an acrylic pressure-sensitive adhesive composition comprising the following components in parts by weight:

[0038] 100 parts acrylic pressure-sensitive adhesive, 15-25 parts modified C5 petroleum resin, and 0.1-0.5 parts crosslinking agent.

[0039] In this invention, the acrylate pressure-sensitive adhesive is obtained by copolymerizing isooctyl acrylate, butyl acrylate, vinyl acetate and acrylic acid; the mass ratio of isooctyl acrylate, butyl acrylate, vinyl acetate and acrylic acid is (70-80):(5-15):(2-8):(5-15).

[0040] In this invention, the crosslinking agent includes aluminum acetylacetonate.

[0041] The present invention will be further described below with reference to embodiments. Unless otherwise defined, the technical or scientific terms used in this invention should have the ordinary meaning understood by one of ordinary skill in the art. The features mentioned above or in the specific examples mentioned in this invention can be combined arbitrarily, and these specific embodiments are only used to illustrate the invention and are not intended to limit the scope of the invention.

[0042] In the following embodiments and comparative examples of the present invention, the manufacturer of C5 petroleum resin is Zibo Luhua Hongjin New Material Group Co., Ltd., and the grade is A1100SZ.

[0043] Example 1

[0044] This embodiment provides a method for preparing modified C5 petroleum resin, comprising the following steps:

[0045] 100g of C5 petroleum resin was melted at 125℃, and 7g of maleic anhydride and 3g of acrylic acid were added under stirring. After mixing evenly, the temperature was raised to 170℃ and reacted for 2 hours to obtain the intermediate product.

[0046] 1 g of di-tert-butyl peroxide (DTBP) was added to the intermediate product, and the reaction was continued at 155 °C for 1.5 h. After the reaction was completed, the product was naturally cooled to room temperature to obtain the modified C5 petroleum resin.

[0047] Example 2

[0048] This embodiment provides a method for preparing modified C5 petroleum resin, comprising the following steps:

[0049] 100g of C5 petroleum resin was melted at 120℃, and 6g of maleic anhydride and 4g of acrylic acid were added under stirring. After mixing evenly, the temperature was raised to 165℃ and the reaction was carried out for 2.5h to obtain the intermediate product.

[0050] 0.5 g of di-tert-butyl peroxide (DTBP) was added to the intermediate product, and the reaction was continued at 150 °C for 2 h. After the reaction was completed, the product was naturally cooled to room temperature to obtain the modified C5 petroleum resin.

[0051] Example 3

[0052] This embodiment provides a method for preparing modified C5 petroleum resin, comprising the following steps:

[0053] 100g of C5 petroleum resin was melted at 130℃, and 9g of maleic anhydride and 2g of acrylic acid were added under stirring. After mixing evenly, the temperature was raised to 175℃ and the reaction was carried out for 1.5h to obtain the intermediate product.

[0054] 1.5 g of di-tert-butyl peroxide (DTBP) was added to the intermediate product, and the reaction was continued at 160 °C for 1 h. After the reaction was completed, the product was naturally cooled to room temperature to obtain the modified C5 petroleum resin.

[0055] Comparative Example 1

[0056] This comparative example provides a method for preparing modified C5 petroleum resin, comprising the following steps:

[0057] 100g of C5 petroleum resin was melted at 125℃. 7g of maleic anhydride, 3g of acrylic acid, and 1g of di-tert-butyl peroxide (DTBP) were added under stirring. After mixing evenly, the temperature was raised to 170℃ and the reaction was carried out for 3.5h. After the reaction was completed, the mixture was naturally cooled to room temperature to obtain modified C5 petroleum resin.

[0058] Comparative Example 2

[0059] This comparative example uses the C5 petroleum resin from the examples.

[0060] Comparative Example 3

[0061] This comparative example uses rosin ester resin (purchased from Guangdong Kemao Forestry Chemical Co., Ltd., KF454).

[0062] Experimental Example 1

[0063] The solubility parameters of the resins in Examples 1-3 and Comparative Examples 1-3 were tested. The specific method is as follows: Six solvents with different solubility parameters were selected, namely n-heptane (15.1 J). 0.5 / cm 1.5 ), cyclohexane (16.7J) 0.5 / cm 1.5 ), Toluene (18.2J) 0.5 / cm 1.5 ethyl acetate (18.6 J) 0.5 / cm 1.5 ), isopropanol (23.6J) 0.5 / cm 1.5 ), ethanol (26.5J) 0.5 / cm 1.5 During the test, each resin was thoroughly mixed with the six solvents mentioned above at a mass ratio of 1:6. After stirring evenly, the mixture was allowed to stand for 24 hours. The solubility of the resin in each solvent was observed and evaluated, and scored according to the following criteria: 4 points indicates that the system is completely dissolved and clear; 3 points indicates that the system is slightly turbid; 2 points indicates that the system is relatively turbid; 1 point indicates partial compatibility, with visible undissolved resin; 0 points indicates that the system is completely insoluble, with the resin and solvent separated into layers. The formula for calculating the solubility parameter (A) for each resin is as follows: , where a i b is the solubility parameter for solvents with a score ≥ 3. i The weight of this solvent's score in the total score of all solvents with a score ≥3 is calculated as (this solvent's score / the sum of the scores of all solvents with a score ≥3). The obtained solubility parameter test results are recorded in Table 1. Furthermore, the solubility parameter of APSA is calculated as: δ = ∑φ i δ i δ is the solubility parameter of APSA; φ i δ represents the mass percentage of each component. i The solubility parameters for each component are given. The solubility parameter for APSA (formulation: 75g isooctyl acrylate, 10g butyl acrylate, 5g vinyl acetate, and 10g acrylic acid) is 18.69J. 0.5 / cm 1.5 .

[0064] Table 1. Solubility parameter test results

[0065] ;

[0066] As shown in Table 1, the modified C5 petroleum resins prepared by the two-step method in Examples 1-3 of this invention have significantly higher solubility parameters than the unmodified Comparative Example 2 (C5 petroleum resin). Furthermore, by adjusting the raw material ratio, the solubility parameters can be stably controlled within the range of 18.2-18.6, which is extremely close to the solubility parameter of APSA (18.69) (absolute difference ≤ 0.49), indicating excellent compatibility. In contrast, the modified resin of Comparative Example 1 (one-step method) shows limited polarity improvement (17.8), with a larger difference from APSA (0.89). Although the solubility parameter of Comparative Example 3 (rosin ester) (18.2) is comparable to some examples of this invention, its thermal stability is generally poor and it is prone to discoloration. The modification method of this invention demonstrates significant advantages in the precision and stability of polarity control.

[0067] Experimental Example 2

[0068] The resins from Examples 1-3 and Comparative Examples 1-3 were prepared into acrylate pressure-sensitive adhesive compositions for performance testing. First, an APSA matrix solution was prepared: 75g of isooctyl acrylate, 10g of butyl acrylate, 5g of vinyl acetate, and 10g of acrylic acid were mixed to obtain a mixed monomer; 0.5g of azobisisobutyronitrile and 20g of ethyl acetate were mixed to obtain an initiator solution; 80g of ethyl acetate and 30g of the mixed monomer were mixed, and the mixture was heated to 70°C under a nitrogen atmosphere and stirring, and kept at this temperature for 10 minutes to stabilize the system. Then, the remaining mixed monomer and initiator solution were simultaneously added dropwise (total addition time was 2.5 hours) to the system. The reaction was continued at 70°C with stirring for 5.5 hours. After the reaction was completed, the mixture was allowed to cool naturally, and samples were taken to determine the solid content. The target solid content was set at 50% (either by adding ethyl acetate (if the solid content is too high) or by re-preparing the solution (if the solid content is too low)). Finally, the solution was filtered through a 200-mesh filter to obtain the APSA matrix solution.

[0069] Then, taking Example 1 as an example, the acrylic pressure-sensitive adhesive composition was prepared as follows: 200g of APSA matrix solution (solid content 50%) was taken, 20g of the resin from Example 1 and 0.3g of aluminum acetylacetonate were added, and an appropriate amount of ethyl acetate was added for dilution. The mixture was stirred thoroughly in a 60°C constant temperature water bath until a homogeneous solution (solid content 34%) was formed. The solution was then uniformly coated onto release paper, and the wet film thickness was controlled to be 25g / m². 2The coated samples were immediately placed in a preheated 130℃ oven and dried for 5 minutes to completely remove the solvent. After removal, the adhesive film with the release paper removed was laminated with a PET film to create standard samples. All samples were placed in a 50℃ oven for 24 hours to ensure sufficient and complete cross-linking reaction. They were then removed and equilibrated in a standard testing environment (23±2℃, 50±10%RH) for 2 hours. Performance tests were conducted according to the following national standards: initial tack strength test according to GB / T 31125-2014, peel strength test according to GB / T 2792-2014 (peel speed: 300mm / min), and holding power test according to GB / T 4851-2014. Failure time was recorded. The performance test results are recorded in Table 2.

[0070] Table 2 Performance Test Results

[0071] ;

[0072] As can be seen from Table 2, the pressure-sensitive adhesive compositions of Examples 1-3 exhibit significantly better initial tack and peel strength than Comparative Examples 1 and 2. In terms of holding power, the product of this invention is far superior to Comparative Examples 3 and 1. This fully demonstrates that the efficient and uniform modification achieved by the two-step process of this invention not only significantly improves adhesion performance but also exceptionally alleviates the decline in holding power, successfully overcoming the challenge of performance balance.

[0073] Therefore, this invention employs the aforementioned method for preparing modified C5 petroleum resin. Through the synergistic effect of polar modifiers (increasing polarity) and functional monomers (assisting in regulating reactivity and polarity distribution), combined with precise control of the initiator, stable regulation of the solubility parameters of the modified C5 petroleum resin is achieved, significantly reducing the difference in solubility parameters between it and APSA, thereby greatly improving its compatibility with APSA. When the modified C5 petroleum resin prepared by the above method is compounded with APSA and a crosslinking agent, on the one hand, the tackifying effect of the modified resin and the tackiness of APSA synergistically enhance each other, significantly improving the initial tack strength and peel strength of the pressure-sensitive adhesive; on the other hand, the crosslinking agent reacts with the polar groups in APSA and the modified resin to form a dynamic crosslinking network, enhancing the cohesive force of the system, effectively inhibiting molecular chain creep caused by the addition of tackifying resin, and significantly alleviating the contradiction in traditional tackifying systems where "increased initial tack strength and peel strength are accompanied by a significant decrease in holding power," thus achieving synergistic optimization of the overall performance of the pressure-sensitive adhesive.

[0074] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the technical solutions of the present invention, and these modifications or equivalent substitutions cannot cause the modified technical solutions to deviate from the spirit and scope of the technical solutions of the present invention.

Claims

1. A method for preparing modified C5 petroleum resin, characterized in that, Includes the following steps: S1. Molten C5 petroleum resin, polar modifier and functional monomer are mixed and subjected to the first reaction to obtain intermediate product; S2. Mix the intermediate product and the initiator to carry out the second reaction and obtain the modified C5 petroleum resin; In S1, the polar modifier includes maleic anhydride, and the functional monomer includes acrylic acid; the mass ratio of molten C5 petroleum resin, polar modifier and functional monomer is 100:(6-9):(2-4). In S1, the temperature of the first reaction is 165-175℃, and the time is 1.5-2.5h; In S2, the initiator includes di-tert-butyl peroxide; the mass ratio of molten C5 petroleum resin to initiator is 100:(0.5-1.5). In S2, the temperature of the second reaction is 150-160℃ and the time is 1-2h.

2. The method for preparing modified C5 petroleum resin according to claim 1, characterized in that, In S1, the method for preparing molten C5 petroleum resin includes: heating C5 petroleum resin to obtain molten C5 petroleum resin. The heating temperature is 120-130℃.

3. A modified C5 petroleum resin, characterized in that, The modified C5 petroleum resin is prepared according to the method described in claim 1 or 2.

4. An acrylic pressure-sensitive adhesive composition, characterized in that, The components include the following parts by mass: 100 parts of acrylate pressure-sensitive adhesive, 15-25 parts of the modified C5 petroleum resin as described in claim 3, and 0.1-0.5 parts of crosslinking agent.

5. The acrylate pressure-sensitive adhesive composition according to claim 4, characterized in that, Acrylic pressure-sensitive adhesive is obtained by copolymerizing isooctyl acrylate, butyl acrylate, vinyl acetate and acrylic acid; the mass ratio of isooctyl acrylate, butyl acrylate, vinyl acetate and acrylic acid is (70-80):(5-15):(2-8):(5-15).

6. The acrylate pressure-sensitive adhesive composition according to claim 4, characterized in that, Crosslinking agents include aluminum acetylacetonate.