High-softening-point terpene styrene resin and preparation method thereof

Abstract

The invention discloses a high-softening-point terpene styrene resin and a preparation method thereof, and belongs to the technical field of high polymer materials, and the key point of the technical scheme is that the high-softening-point terpene styrene resin adopts the following technical scheme: the preparation method of the high-softening-point terpene styrene resin is used for preparing the high-softening-point terpene styrene resin. Comprising the following steps: S1, mixing styrene and myrcene to obtain a mixed monomer; s2, uniformly mixing butyl acetate and a catalyst at the temperature of less than or equal to 15 DEG C; s3, when the temperature of the system in the step S2 is less than or equal to 10 DEG C, dropwise adding a mixed monomer, and after dropwise adding, carrying out heat preservation and discharging to obtain a polymer solution; s4, the polymer liquid is washed with hot water to be neutral and then distilled, and the high-softening-point terpene-styrene resin is obtained.According to the method, styrene, myrcene and butyl acetate are matched, the terpene-styrene resin higher in molecular weight and longer in molecular chain can be formed, and the softening point of the terpene-styrene resin is made to be larger than or equal to 130 DEG C.

Description

Technical Field

[0001] This invention relates to the field of polymer materials technology, and in particular to a high softening point terpene styrene resin and its preparation method. Background Technology

[0002] In the field of polymer materials, with the continuous development of industry, the demand for various high-performance resin materials is increasing. Polymer materials, with their unique physical and chemical properties, play a vital role in many industries. For example, in adhesives and rubber products, suitable resin materials can significantly improve product performance and quality. Among them, terpene styrene resin, as an important polymer material, has broad application prospects in various adhesives such as hot melt adhesives, pressure-sensitive adhesives, and acrylic adhesives, as well as rubber products, due to its colorless or pale yellow solid appearance and excellent thermal stability, good flowability, and adhesion. It not only provides good adhesion for adhesives but also improves the weather resistance and gloss of coatings, making it valuable in both industrial production and daily life.

[0003] Traditionally, the preparation of terpene-styrene resins has typically employed conventional free radical polymerization. Specifically, this involves mixing terpenes and styrene monomers and then inducing a polymerization reaction under specific conditions. This method is widely used in many production practices and is a common approach in this field. During the reaction, basic conditions such as temperature and pressure are controlled to ensure its smooth progress. Common catalysts are also added to accelerate the reaction. Furthermore, the post-reaction product is typically processed using conventional separation and purification steps such as washing and distillation to obtain terpene-styrene resin products that meet specific quality standards.

[0004] However, existing preparation methods for terpene-styrene resins have significant drawbacks. Currently, the highest softening point of these conventional methods is only 100°C, making them unsuitable for high-temperature applications and greatly limiting their scope of use. In some high-temperature industrial applications where a high softening point is critical, existing terpene-styrene resins cannot meet practical requirements. Summary of the Invention

[0005] To address the problems in the prior art, this invention provides a high softening point terpene styrene resin and its preparation method. This application combines styrene, myrcene, and butyl acetate to form a terpene styrene resin with higher molecular weight and longer molecular chains, resulting in a softening point of ≥130℃ for the terpene styrene resin.

[0006] The first aspect of this invention is to provide a high softening point terpene styrene resin, which adopts the following technical solution: A method for preparing a high softening point terpene styrene resin includes the following steps: S1. Styrene and myrcene are mixed to obtain a mixed monomer; S2. Mix butyl acetate and catalyst evenly at a temperature ≤15℃; S3. When the temperature of the system in step S2 is ≤10℃, add the mixed monomer dropwise. After the addition is complete, keep the temperature and discharge the material to obtain the polymerization liquid. S4. The polymerization solution is washed with hot water until neutral and then distilled to obtain a high softening point terpene styrene resin.

[0007] In a preferred embodiment, the amount of styrene is 30-40% and the amount of myrcene is 60-70% by weight percentage.

[0008] By employing the above technical solution, copolymerizing styrene and myrcene under butyl acetate can yield a terpene styrene resin with a softening point ≥130℃. The reason is that myrcene is an open-chain monoterpene containing three carbon-carbon double bonds, two of which are conjugated double bonds. This structural formula has higher chemical reactivity and is more prone to chain growth reactions. When copolymerized with styrene, it can form polymers with higher molecular weight and longer molecular chains. Generally, higher molecular weight is directly associated with a higher softening point. Furthermore, the introduction of myrcene will form a more rigid sequence distribution with styrene. Its long-chain aliphatic structure can form more effective molecular chain entanglement after polymerization, thereby greatly increasing the cohesive energy of the polymer and significantly improving its heat resistance and softening point.

[0009] Furthermore, when butyl acetate, which has lower polarity, is used as the solvent in this application, its chain transfer performance is better than that of toluene, which is beneficial to the growth of polymer chains to obtain terpene styrene resin with a high softening point.

[0010] In addition, in the above preparation method of this application, steps S2 and S3 are both carried out at a low temperature, which can effectively suppress side reactions, make the polymerization reaction proceed smoothly, and is conducive to obtaining a high softening point polymer with a narrower molecular weight distribution and a more regular structure.

[0011] In a preferred embodiment, the mass ratio of butyl acetate to the mixed monomers is 1:1.

[0012] In a preferred embodiment, the catalyst is added at an amount of 2.4-2.6% of the total weight of the mixed monomers.

[0013] In a preferred embodiment, the distillation temperature is 240-250°C and the vacuum degree is -0.085 to -0.099 MPa.

[0014] In a preferred embodiment, in step S3, when adding the mixed monomers, the addition is stopped when the system temperature begins to rise, and the addition continues when the system temperature reaches 50-55°C. The mixture is then discharged after being kept at 50-55°C for 1.8-2 hours.

[0015] By adopting the above technical solution, since the reaction between styrene and myrcene is exothermic due to the catalytic effect, when the system temperature rises, it indicates that the reaction has been initiated and is proceeding at an extremely high rate. If the mixed monomers are continued to be added, the reaction temperature will be even higher, increasing the risk factor of the entire reaction process. At high temperatures, side reactions will increase, and the rates of chain transfer and chain termination will vary, resulting in uneven molecular weight of the polymer and uncontrollable product structure. For example, excessively high temperatures may cause myrcene to produce too much crosslinking, which will lower the softening point of the final polymer. When the system temperature is maintained in the range of 50-55℃, the stable and controllable polymerization of the mixed monomers can be achieved, which is conducive to the formation of polymers with more regular structures and higher softening points.

[0016] In a preferred embodiment, in step S4, the polymer solution is washed with hot water at 95-100°C.

[0017] By adopting the above technical solution, multiple water washings with hot water at 95-100℃ can effectively remove catalysts and impurities from the polymerization solution, ensuring the purity of the terpene styrene resin.

[0018] In a preferred embodiment, the moisture content of the mixed monomers is controlled to be below 300 ppm after mixing.

[0019] In a preferred embodiment, the catalyst is aluminum trichloride.

[0020] A second aspect of the present invention is to provide a terpene styrene resin obtained by the preparation method of the high softening point terpene styrene resin as described above, wherein the softening point of the terpene styrene resin is ≥130°C.

[0021] In summary, the present invention has the following beneficial effects: This application demonstrates that copolymerizing terpene styrene resin with styrene monomers using myrcene instead of turpentine (whose main components are α-pinene and β-pinene) under butyl acetate yields a high-softening-point terpene styrene resin with well-defined polymer chains and appropriate molecular weight, thus meeting the application requirements in high-temperature scenarios and filling a domestic gap. Furthermore, the amount of styrene monomer used in this application is between 30-40%, breaking the existing understanding that the softening point of terpene styrene resin is significantly reduced when the styrene monomer content is above 15%. Moreover, the large amount of styrene monomer not only reduces the amount of myrcene monomer used, lowering preparation costs, but also ensures the low polarity of the terpene styrene resin while maintaining a styrene content above 30%. This results in hot melt adhesives made from high-softening-point terpene styrene resin exhibiting high adhesion to polar substrates such as PC, glass, metal, and rubber tires, thus possessing greater application value. Attached Figure Description

[0022] Figure 1 This is a screenshot of the molecular weight test report for the terpene styrene resin of Example 1 of this application.

[0023] Figure 2 This is the infrared spectrum of the molecular structure of the terpene styrene resin of Example 1 of this application.

[0024] Figure 3 This is a screenshot of the molecular weight test report for the terpene styrene resin of Comparative Example 1 of this application.

[0025] Figure 4 This is a screenshot of the molecular weight test report for the terpene styrene resin of Comparative Example 2 of this application.

[0026] Figure 5 This is a screenshot of the molecular weight test report for the terpene styrene resin of Comparative Example 3 of this application. Detailed Implementation

[0027] The present invention will be further described in detail below with reference to the accompanying drawings. All reagents, unless otherwise specified, are commercially available conventional reagent products.

[0028] In existing technologies, terpene styrene resin is obtained by copolymerizing 85% turpentine (mainly composed of α-pinene and β-pinene) and 15% styrene in toluene solvent to obtain a resin with a softening point of 100-115℃. Furthermore, the softening point decreases with increasing styrene content because the increased styrene content weakens the cross-linking between resin molecules, leading to a looser three-dimensional network structure, reduced resistance to molecular chain movement, and consequently, a lower softening point. However, this application, by using myrcene instead of turpentine and increasing the amount of styrene monomer added, also obtains a terpene styrene resin with a softening point ≥130℃. This not only fills a domestic gap but also overcomes the bottleneck of decreased softening point when the styrene monomer content is increased beyond 15% in existing technologies. Moreover, the addition of a large amount of styrene monomer results in better compatibility, initial tack, and toughness of the high-softening-point terpene styrene resin.

[0029] Example 1

[0030] A method for preparing a high softening point terpene styrene resin includes the following steps: S1. Based on the proportion of styrene 30wt% and myrcene 70%, 1650g of styrene and 3850g of myrcene were stirred and mixed for 30 minutes, then left to stand for 30 minutes and the water was separated to obtain a mixed monomer with a water content of 300ppm. The myrcene used was turpentine myrcene. S2. Add 5500g of anhydrous butyl acetate to the polymerization reactor and stir. When the temperature inside the reactor drops to 15℃, add 132g of aluminum trichloride catalyst and continue stirring and mixing. The amount of catalyst added is 2.4% of the total amount of the mixed monomers. S3. When the temperature inside the reactor in step S2 drops to 10°C, add the mixed monomer dropwise. Stop adding the monomer dropwise when the system temperature starts to rise to 22°C. Continue adding the monomer dropwise when the system temperature rises to 50°C until all the mixed monomer has been added. After keeping the mixture at 50°C for 2 hours, discharge the polymer solution. The yield of the polymer solution is 92%. S4. The polymerization solution is washed with water at 95℃ until neutral and then allowed to stand for 30 minutes. The water in the polymerization solution is drained, and then it is added to a distillation kettle for distillation to remove the solvent. The distillation temperature is 240℃ and the vacuum degree is -0.085MPa. After distillation for 30 minutes, the material is discharged and granulated to obtain high softening point terpene styrene resin.

[0031] Example 2

[0032] The difference from Example 1 lies in the changes of the parameters, as detailed below. A method for preparing a high softening point terpene styrene resin includes the following steps: S1. Based on the proportion of styrene 35wt% and myrcene 65%, 1925g of styrene and 3575g of myrcene were stirred and mixed for 30 minutes, then left to stand for 30 minutes and the water was separated to obtain a mixed monomer with a water content of 300ppm. The myrcene used was turpentine myrcene. S2. Add 5500g of anhydrous butyl acetate to the polymerization reactor and stir. When the temperature inside the reactor drops to 15℃, add 137.5g of aluminum trichloride catalyst and continue stirring and mixing. The amount of catalyst added is 2.5% of the total amount of the mixed monomers. S3. When the temperature inside the reactor in step S2 drops to 10°C, add the mixed monomer dropwise. Stop adding the monomer dropwise when the system temperature starts to rise to 21°C. Continue adding the monomer dropwise when the system temperature rises to 55°C until all the mixed monomer has been added. Then, keep the mixture at 55°C for 1.8 hours and discharge the polymer solution. The yield of the polymer solution is 91%. S4. The polymerization solution is washed with water in 100℃ hot water until neutral, and then left to stand for 30 minutes. The water in the polymerization solution is drained, and then it is added to a distillation kettle for distillation to remove the solvent. The distillation temperature is 250℃ and the vacuum degree is -0.099MPa. After distillation for 30 minutes, the material is discharged and granulated to obtain high softening point terpene styrene resin.

[0033] Example 3

[0034] The difference from Example 1 lies in the changes of the parameters, as detailed below. A method for preparing a high softening point terpene styrene resin includes the following steps: S1. Based on the proportion of styrene as 40wt% and myrcene as 60%, 2200g of styrene and 3300g of myrcene were stirred and mixed for 30 minutes, then left to stand for 30 minutes and the water was separated to obtain a mixed monomer with a water content of 300ppm. The myrcene used was turpentine myrcene. S2. Add 5500g of anhydrous butyl acetate to the polymerization reactor and stir. When the temperature inside the reactor drops to 15℃, add 143g of aluminum trichloride catalyst and continue stirring and mixing. The amount of catalyst added is 2.6% of the total amount of the mixed monomers. S3. When the temperature inside the reactor in step S2 drops to 10°C, add the mixed monomers dropwise. Stop adding the monomers when the system temperature starts to rise to 22°C. Continue adding the monomers dropwise when the system temperature rises to 55°C until all the mixed monomers have been added. After keeping the mixture at 55°C for 2 hours, discharge the polymer solution. The yield of the polymer solution is 91%. S4. The polymerization solution is washed with water in 100℃ hot water until neutral, and then left to stand for 30 minutes. The water in the polymerization solution is drained, and then it is added to a distillation kettle for distillation to remove the solvent. The distillation temperature is 250℃ and the vacuum degree is -0.099MPa. After distillation for 30 minutes, the material is discharged and granulated to obtain high softening point terpene styrene resin.

[0035] Comparative Example 1

[0036] A method for preparing a terpene styrene resin, wherein the styrene content is 30 wt% and the myrcene content is 70%, the method differs from Example 1 in that an equal amount of toluene is used instead of butyl acetate, and all other aspects are the same as in Example 1.

[0037] Comparative Example 2

[0038] A method for preparing a terpene styrene resin differs from Example 1 in that, based on a total mixed monomer content of 5500g, the proportions of styrene and myrcene are 50wt%, while all other aspects are the same as in Example 1.

[0039] Comparative Example 3

[0040] A method for preparing a terpene styrene resin differs from Example 1 in that, based on a total mixed monomer weight of 5500g, the proportion of styrene is 40wt% and the proportion of myrcene is 60wt%, and an equal amount of toluene is used instead of butyl acetate; otherwise, the method is the same as in Example 1.

[0041] Performance testing

[0042] 1. The softening point of the terpene styrene resins obtained in the above examples and comparative examples was tested. The softening point was tested in accordance with the relevant provisions of GB 12007.6-89 "Determination of Softening Point of Epoxy Resins - Ring and Ball Method". The test results are shown in Table 1.

[0043] 2. The terpene styrene resin obtained in Example 1 was subjected to number-average molecular weight determination by chromatography. The results are as follows: Figure 1 As shown, the molecular weight detection results of the terpene styrene resins obtained in other examples are basically similar to those in Example 1, and will not be repeated in the accompanying figures. The number-average molecular weight detection graphs of Comparative Examples 1-3 are shown below. Figure 3-5 As shown.

[0044] 3. The molecular structure and chemical bonds of the terpene styrene resin obtained in Example 1 were detected, and the results are as follows: Figure 2 As shown, the molecular structures of the terpene styrene resins obtained in other embodiments are basically the same as those in Example 1, and the figures will not be repeated.

[0045] Table 1. Performance Test Results of Terpene Styrene Resin project softening point ℃ Number average molecular weight Example 1 135 1000 Example 2 132 986 Example 3 130 968 Comparative Example 1 115 835 Comparative Example 2 90 691 Comparative Example 3 100 796 Based on the test data in Table 1: This application achieves a softening point of 130°C for the terpene styrene resin by controlling the selection of styrene, myrcene, and solvent, thus overcoming the technical bottleneck of low softening point in conventional terpene styrene resins with increased styrene content.

[0046] Compared to Example 1, when the proportions of styrene and myrcene were the same as in Example 1, but butyl acetate was replaced with toluene, the softening point of the terpene styrene resin obtained in Comparative Example 1 was 115°C, which was significantly lower than that of Example 1. Figure 3 As can be seen from this, its Z-average molecular weight value is compared to Figure 1 The significantly reduced Z-average molecular weight indicates that the molecular weight of the polymer chain of the terpene styrene resin obtained in Comparative Example 1 is reduced. This may be because toluene has poorer chain transfer properties than butyl acetate. Therefore, when toluene is used as the solvent, it is impossible to obtain a terpene styrene resin with a higher molecular weight, thus lowering its softening point.

[0047] Compared with Example 1, when the content of styrene and myrcene was both 50%, the softening point of the terpene styrene resin obtained in Comparative Example 2 was 90°C, and its molecular weight was also significantly reduced. This indicates that the addition of excessive styrene will significantly reduce the softening point of the terpene styrene resin.

[0048] Compared with Example 1, when the styrene content was 40%, the myrcene content was 60%, and toluene was used instead of butyl acetate, the softening point of the terpene styrene resin obtained in Comparative Example 3 was 100°C, which was much lower than that in Example 1. This further illustrates that the combination of styrene, myrcene and butyl acetate effectively improved the softening point of the terpene styrene resin.

[0049] 4. Performance testing of sanitary tape: 25g of terpene styrene resin, 15g of SBS, and 10g of naphthenic oil obtained in the above examples or comparative examples were added to 100g of toluene and mixed evenly. The mixture was reacted at room temperature for 12 hours, and then coated onto a substrate with a coating thickness of 200μm. The adhesive was then vacuum dried at 130℃ to obtain a sanitary grade tape. Ring initial tack test, 24-hour peel test, and holding power test were performed. The test results are shown in Table 2. Specific tests are as follows: Ring tack test: The test shall be conducted in accordance with the relevant provisions of GB / T31125-2014 "Test method for initial tack of adhesive tape - ring method".

[0050] 24-hour peel test: The test was conducted in accordance with GB / T2792-2014 "Test method for peel strength of adhesive tape", and the average peel force and peel strength were recorded.

[0051] Holding power: The test was conducted according to Method A in GB / T4851-2014 "Test Method for Holding Power of Adhesive Tapes". The holding power test conditions were as follows: one end of the tape was adhered to a 25mm*25mm area of ​​a stainless steel sample, a 1kg weight was suspended from the lower end, and the test temperature was 40℃.

[0052] Table 2. Performance Test Results of Terpene Styrene Resin

[0053] Continued from Table 2

[0054] Based on the test data in Table 2: The terpene styrene resins obtained in Examples 1-3 of this application have good initial and long-lasting adhesion to both stainless steel and plastics. Furthermore, the peel force at 20 min is basically the same as that at 24 h, which further demonstrates that the adhesives obtained using terpene styrene resins have good initial tack properties.

[0055] Compared with Example 1, the bonding performance of the terpene styrene resin with a softening point of 90-115℃ to stainless steel and plastics in Comparative Examples 1-3 was significantly lower than that of the high softening point terpene styrene resin obtained in Example 1 of this application, which further illustrates that the high softening point terpene styrene resin in this application has good bonding ability.

[0056] The embodiments described herein are preferred embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Therefore, all equivalent changes made in accordance with the structure, shape, and principle of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A method for preparing a high softening point terpene styrene resin, characterized in that, Includes the following steps: S1. Styrene and myrcene are mixed to obtain a mixed monomer; S2. Mix butyl acetate and catalyst evenly at a temperature ≤15℃; S3. When the temperature of the system in step S2 is ≤10℃, add the mixed monomer dropwise. After the addition is complete, keep the temperature and discharge the material to obtain the polymerization liquid. S4. The polymerization solution is washed with hot water until neutral and then distilled to obtain a high softening point terpene styrene resin.

2. The method for preparing a high softening point terpene styrene resin according to claim 1, characterized in that: The amount of styrene is 30-40% and the amount of myrcene is 60-70% by weight percentage.

3. The method for preparing a high softening point terpene styrene resin according to claim 1, characterized in that: The mass ratio of butyl acetate to the mixed monomers is 1:

1.

4. The method for preparing a high softening point terpene styrene resin according to claim 1, characterized in that: The catalyst is added at a rate of 2.4-2.6% of the total weight of the mixed monomers.

5. The method for preparing a high softening point terpene styrene resin according to claim 1, characterized in that: The distillation temperature is 240-250℃, and the vacuum degree is -0.085~-0.099MPa.

6. The method for preparing a high softening point terpene styrene resin according to claim 1, characterized in that: In step S3, when adding the mixed monomers, the addition is stopped when the system temperature begins to rise, and the addition continues when the system temperature reaches 50-55℃. The mixture is then discharged after being kept at 50-55℃ for 1.8-2 hours.

7. The method for preparing a high softening point terpene styrene resin according to claim 1, characterized in that: In step S4, the polymerization solution is washed with hot water at 95-100℃.

8. The method for preparing a high softening point terpene styrene resin according to claim 1, characterized in that: The moisture content of the mixed monomers is controlled to be below 300 ppm after mixing.

9. The method for preparing a high softening point terpene styrene resin according to claim 1, characterized in that: The catalyst is aluminum trichloride.

10. A terpene styrene resin obtained by the preparation method of the high softening point terpene styrene resin according to any one of claims 1-9, characterized in that: The softening point of the terpene styrene resin is ≥130℃.

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