Low-temperature-resistant low-modulus road caulking sealant and preparation method thereof

Abstract

The invention relates to the technical field of adhesives, in particular to a low-temperature-resistant low-modulus road caulking sealant and a preparation method thereof. The low-temperature-resistant low-modulus road caulking sealant is prepared from the following components in parts by weight: 90 to 110 parts of hydroxyl-terminated polydimethylsiloxane, 100 to 200 parts of calcium carbonate, 30 to 60 parts of a plasticizer, 1 to 2 parts of a water removal agent, 10 to 15 parts of a cross-linking agent, 0.1 to 0.5 part of a catalyst and 2 to 5 parts of an adhesion promoter. The low-temperature-resistant low-modulus road caulking sealant prepared by the invention has an excellent elastic recovery rate, and meets the requirement of 25-grade high displacement capability in sealant for road and bridge caulking JC / T 976-2005. The tensile modulus at the normal temperature of 23 DEG C and the low temperature of-20 DEG C is far lower than the standard requirement, the caulking glue is low in stress and not prone to damage in the expansion and contraction process of concrete, concrete debonding is avoided, and the service life is longer.

Description

Technical Field

[0001] The invention relates to the technical field of adhesives, and more specifically to a low-temperature-resistant low-modulus road caulking sealant and a preparation method thereof. Background Art

[0002] Due to the thermal expansion and contraction characteristics of materials, joints must be reserved in road construction to adapt to environmental changes. If the road joints are not sealed well, rainwater will easily penetrate into the road structure layer. Long-term erosion and corrosion will cause holes to form under the road surface, leading to road collapse. In addition, rain and snow enter the foundation in winter, and the resulting freeze-thaw phenomenon will also cause corner collapse and road expansion. Therefore, choosing suitable road caulking materials with excellent performance is an important measure to ensure the quality of road projects and increase the service life of roads.

[0003] According to the actual road construction experience and the analysis of the failure of pavement joints, the performance requirements of road caulking materials should meet the following three aspects: First, good sealing is the key factor in preventing leakage, and good adhesion is a prerequisite for ensuring sealing; second, due to the poor tensile strength of pavement materials such as concrete and asphalt, the pavement joints vary greatly, so the material is required to have a low elastic modulus and high displacement capacity to reduce internal stress and prevent debonding or cracking; finally, since the pavement is exposed to wind, sun, rain and snow for a long time, the temperature in winter can reach -40℃, and the temperature in summer can reach 70~80℃, excellent UV resistance, weather resistance, high and low temperature resistance can effectively prevent colloid aging, increase the service life of the pavement, and extend the repair cycle.

[0004] In summary, road caulking materials should have the following performance characteristics: (1) good adhesion; (2) low modulus; (3) high displacement capacity; (4) resistance to ultraviolet rays and weathering; (5) resistance to high and low temperatures; and (6) good workability.

[0005] Commonly used road caulking materials include asphalt, modified asphalt, polysulfide sealant, polyurethane sealant, etc.

[0006] Asphalt is the earliest road caulking material used. It is cheap and easy to obtain. However, its displacement capacity is not high, and it becomes soft or even flows at high temperatures, and becomes brittle and loses elasticity at low temperatures. Therefore, the sealing effect is not ideal. It is only suitable for occasions where the joint changes little and the ambient temperature changes relatively little. At present, it has been gradually replaced by modified asphalt.

[0007] Compared with asphalt, modified asphalt has improved high and low temperature resistance, but its displacement capacity is still not high, and it is only suitable for occasions where the joint changes little. However, due to its low price, it is now widely used.

[0008] Polysulfide sealant and polyurethane sealant are both room temperature vulcanized rubber products. Both can be made into products with low modulus and high displacement capacity. They are currently widely used in caulking and sealing of roads such as ordinary roads, highways, and airports. Polysulfide road sealant is a two-component material. During construction, the two components need to be mixed evenly and then poured into the joints. It has good oil resistance, so it is widely used in airport aprons. It also has good high and low temperature resistance and can be used in the range of -30 to 80°C, so it can be used in places where the temperature is not particularly low. However, its resistance to ultraviolet aging is not very good. Although the comprehensive performance is good in the initial stage of application, after 1 to 2 years, cracking and hardening will occur, making the seal ineffective and requiring repair or re-caulking.

[0009] Polyurethane road sealant has good oil resistance, high and low temperature resistance and similar application occasions as polysulfide sealant. Its aging resistance is slightly better than that of polysulfide sealant, and it can be used for 2 to 3 years. Generally, it must be repaired or re-filled after 3 years.

[0010] Since the aging resistance of polysulfide and polyurethane road sealants is not very good, a thicker glue filling thickness is often required during the construction process, so that even if the surface is aged to a certain extent, the deep layer can still maintain a certain sealing effect. Summary of the invention

[0011] The purpose of the present invention is to provide a low-temperature resistant low-modulus road caulking sealant and a preparation method thereof. The low-temperature resistant low-modulus road caulking sealant is used to solve the technical problem that the existing road caulking materials fail to have the above six performance characteristics at the same time.

[0012] The above technical objectives of the present invention are achieved through the following technical solutions:

[0013] A low-temperature resistant low-modulus road caulking sealant comprises, by weight, 90-110 parts of hydroxyl-terminated polydimethylsiloxane, 100-200 parts of calcium carbonate, 30-60 parts of plasticizer, 1-2 parts of dewatering agent, 10-15 parts of cross-linking agent, 0.1-0.5 parts of catalyst and 2-5 parts of adhesion promoter.

[0014] Preferably, the hydroxyl-terminated polydimethylsiloxane has a viscosity of 20,000 to 500,000 mPa.s at 25° C., or a combination of the two.

[0015] Preferably, the calcium carbonate is heavy calcium carbonate treated with stearic acid, and its particle size is 800-1500 meshes.

[0016] Preferably, the plasticizer is methyl silicone oil, and its kinematic viscosity is 100-1000 mPa·s at 25° C. Adding methyl silicone oil as a plasticizer can improve the fluidity of the road caulking sealant and increase its elongation at break.

[0017] Preferably, the dehydrating agent is one of vinyl trimethoxy silane and 3-isocyanate propyl triethoxy silane.

[0018] Preferably, the crosslinking agent is one of methyltributylacetoximine silane, vinyltributylacetoximine silane, phenyltributylacetoximine silane or a combination thereof.

[0019] Preferably, the catalyst is one of dibutyltin diacetate, dibutyltin dilaurate, and dibutyltin bis(acetylacetonate).

[0020] Preferably, the adhesion promoter is one of 1146 (Evonik silane coupling agent), KH792 (γ-aminoethylaminopropyltrimethoxysilane), VX225 (Momentive silane coupling agent) or a combination thereof.

[0021] Another object of the present invention is to provide a method for preparing the aforementioned low-temperature resistant low-modulus road caulking sealant, which comprises the following steps:

[0022] S1: Add hydroxyl-terminated polydimethylsiloxane, calcium carbonate and black slurry into a planetary mixer with heating function, dehydrate and mix for 120 to 180 minutes at a temperature of 120 to 150° C. and a vacuum degree of 0.085 to 0.095 MPa;

[0023] S2: Add plasticizer, stir slowly, and pass cooling water or ice water to reduce the material temperature to below 40°C before proceeding to the next step;

[0024] S3: Add dehydrating agent and stir for 15 to 20 minutes at a vacuum degree of 0.085 to 0.095 Mp and a rotation speed of 20 to 25 Hz;

[0025] S4: adding the crosslinking agent, the catalyst and the adhesion promoter into a planetary mixer, stirring for 20 to 40 minutes at a vacuum degree of 0.085 to 0.095 Mp and a rotation speed of 20 to 25 Hz to obtain the low-temperature resistant low-modulus road caulking sealant.

[0026] In summary, the embodiments provided by the above technical solutions of the present invention have the following beneficial effects:

[0027] The low-temperature-resistant low-modulus road caulking sealant of the present invention has excellent elastic recovery rate and meets the requirement of 25-level high displacement capacity in JC / T 976-2005 "Road and Bridge Caulking Sealant". The tensile modulus at room temperature 23°C and low temperature -20°C is far lower than the standard requirement. In the process of concrete thermal expansion and contraction, the caulking sealant has low stress, is not easily damaged, and will not cause concrete debonding, so it has a longer service life.

[0028] The low-temperature-resistant low-modulus road caulking sealant of the present invention is a single-component product, which is easy to construct and does not require pre-mixing. Silicone adhesive has excellent resistance to ultraviolet aging lines and can ensure that cracking, powdering, hardening and the like will not occur for 10 years. Therefore, its construction thickness only needs to be 6 to 13 mm, and the amount used is much lower than that of polysulfide adhesive and polyurethane adhesive. In addition, the high and low temperature resistance of silicone adhesive is also very good, and it can maintain elasticity at -50 to 150°C, does not harden or become brittle at low temperatures, and does not soften or flow at high temperatures. DETAILED DESCRIPTION

[0029] In order to make the purpose, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are described in detail below. Several embodiments of the present invention are given. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein.

[0030] Example 1

[0031] The present embodiment provides a low-temperature resistant and low-modulus road caulking sealant, which includes, by weight, 100 parts of hydroxyl-terminated polydimethylsiloxane, 140 parts of calcium carbonate, 0.05 parts of black paste, 50 parts of plasticizer, 1.2 parts of dewatering agent, 12 parts of cross-linking agent, 0.15 parts of catalyst, and 3 parts of adhesion promoter.

[0032] Among them, the viscosity of hydroxyl-terminated polydimethylsiloxane at 25°C is 80000mpa.s, the particle size of calcium carbonate is 1250 mesh, the plasticizer is methyl silicone oil and the viscosity at 25°C is 350mpa.s, the dehydrating agent is 3-isocyanatepropyltriethoxysilane, the cross-linking agent is a mixture of phenyltributylacetonato silane and methyltributylacetonato silane, the catalyst is dibutyltin dilaurate, and the adhesion promoter is a mixture of 1146 and VX225.

[0033] The above-mentioned low-temperature resistant low-modulus road caulking sealant is prepared by the following preparation method, which comprises the following steps:

[0034] S1: Add hydroxyl-terminated polydimethylsiloxane, calcium carbonate and black slurry into a planetary mixer with heating function, dehydrate and mix for 150 minutes at a temperature of 130°C and a vacuum degree of 0.09 MPa;

[0035] S2: Add plasticizer, stir slowly, and pass cooling water to reduce the material temperature to 40°C before proceeding to the next step;

[0036] S3: Add dehydrating agent and stir for 20 min at vacuum degree 0.09 Mp and rotation speed 25 Hz;

[0037] S4: Add the crosslinking agent, catalyst and adhesion promoter into a planetary mixer, stir for 30 minutes at a vacuum degree of 0.09 Mp and a rotation speed of 25 Hz to prepare a low-temperature resistant low-modulus road caulking sealant.

[0038] Example 2

[0039] The raw material composition thereof is different from that of Example 1 in that the adhesion promoter is only 1146 and does not contain VX225. The preparation method thereof is the same as that of Example 1.

[0040] Example 3

[0041] The raw material composition thereof is different from that of Example 1 in that the adhesion promoter is only KH792. The preparation method thereof is the same as that of Example 1.

[0042] Comparative Example 1

[0043] The difference between the raw material composition and that of Example 1 is that the calcium carbonate is not treated with stearic acid. The preparation method is the same as that of Example 1.

[0044] Comparative Example 2

[0045] The raw material composition thereof is different from that of Example 1 in that the adhesion promoter is only KH550. The preparation method thereof is the same as that of Example 1.

[0046] Comparative Example 3

[0047] The difference between the raw material composition and that of Example 1 is that the crosslinking agent is only methyl tributylidene oxime silane. The preparation method is the same as that of Example 1.

[0048] The formulations of each embodiment and comparative example are as follows:

[0049] Table 1 Formulas of Examples and Comparative Examples

[0050]

[0051]

[0052] The sealants prepared in the above embodiments and comparative examples were tested for performance. The test substrate used a cement mortar board, and the substrate surface was free of oil stains and floating sand. The following performances were tested in accordance with JC / T 976-2005 "Sealant for Caulking of Roads and Bridges":

[0053] Table 2 Performance data of examples and comparative examples

[0054]

[0055]

[0056] It can be seen from the data of the examples and comparative examples in Table 2 that examples 1-3 all meet the 25LM requirements in JC / T976-2005, among which example 1 is better in elastic recovery rate and -20℃ tensile modulus, example 1 is better in low temperature resistance and has a lower modulus; compared with example 1, example 1 uses heavy calcium carbonate that has not been treated with fatty acids, and the extrudability is too high and too flowing, and the construction performance is poor. In actual use, the caulking glue is easy to leak from the gap of the foam rod, forming a cavity phenomenon. Compared with example 1, example 2 uses KH550 as an adhesion promoter, not only the modulus is high, but also the cement mortar board debonds in the fixed extension test. In actual use, the caulking glue and the cement expansion joint are easy to debond, and the seal fails. Compared with example 1, example 3 only uses methyl tributylidene oxime silane as a crosslinking agent, and the tensile modulus of example 3 is high, which does not meet the 25LM requirements.

[0057] In summary, the present invention selects suitable calcium carbonate and uses different cross-linking agents and adhesion promoters to compound the sealant, so that the sealant has the characteristics of high displacement capacity and low modulus under various temperature conditions; secondly, the sealant has good adhesion to concrete, making it a road caulking material with excellent performance, which greatly prolongs the maintenance cycle of concrete pavement and reduces maintenance costs.

[0058] The above is only a preferred embodiment of the present invention, and the protection scope of the present invention is not limited to the above embodiments. All technical solutions under the concept of the present invention belong to the protection scope of the present invention. It should be pointed out that for ordinary technicians in this technical field, some improvements and modifications without departing from the principle of the present invention should also be regarded as the protection scope of the present invention.

Claims

1. Low temperature resistant low modulus road caulking sealant, characterized by: Calculated by weight, it includes 90-110 parts of hydroxyl-terminated polydimethylsiloxane, 100-200 parts of calcium carbonate, 30-60 parts of plasticizer, 1-2 parts of dewatering agent, 10-15 parts of cross-linking agent, 0.1-0.5 parts of catalyst and 2-5 parts of adhesion promoter.

2. The low-temperature resistant low-modulus road caulking sealant according to claim 1, characterized in that: The calcium carbonate is heavy calcium carbonate treated with stearic acid, and its particle size is 800-1500 meshes.

3. The low-temperature resistant low-modulus road caulking sealant according to claim 1, characterized in that: The plasticizer is methyl silicone oil.

4. The low-temperature resistant low-modulus road caulking sealant according to claim 1, characterized in that: The dewatering agent is one of vinyl trimethoxy silane and 3-isocyanate propyl triethoxy silane.

5. The low-temperature resistant low-modulus road caulking sealant according to claim 1, characterized in that: The crosslinking agent is one of methyltributylacetoximosilane, vinyltributylacetoximosilane, phenyltributylacetoximosilane or a combination thereof.

6. The low-temperature resistant low-modulus road caulking sealant according to claim 1, characterized in that: The catalyst is one of dibutyltin diacetate, dibutyltin dilaurate and dibutyltin bis(acetylacetonate).

7. The low-temperature resistant low-modulus road caulking sealant according to claim 1, characterized in that: The adhesion promoter is one of 1146, KH792, VX225 or a combination thereof.

8. The method for preparing the low-temperature resistant low-modulus road caulking sealant according to any one of claims 1 to 7, characterized in that: The following steps are involved: S1: Add hydroxyl-terminated polydimethylsiloxane, calcium carbonate and black slurry into a planetary mixer with heating function, dehydrate and mix for 120 to 180 minutes at a temperature of 120 to 150° C. and a vacuum degree of 0.085 to 0.095 MPa; S2: Add plasticizer, stir slowly, and pass cooling water or ice water to reduce the material temperature to below 40°C before proceeding to the next step; S3: Add dehydrating agent and stir for 15 to 20 minutes at a vacuum degree of 0.085 to 0.095 Mp; S4: adding a crosslinking agent, a catalyst and an adhesion promoter into a planetary mixer, stirring for 20 to 40 minutes at a vacuum degree of 0.085 to 0.095 Mp, to obtain the low-temperature resistant low-modulus road caulking sealant.

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