Antiskid plastic bottle cap and preparation method thereof

Abstract

The invention discloses an anti-skid plastic bottle cap and a preparation method thereof, and relates to the technical field of plastic bottle caps, the anti-skid plastic bottle cap comprises a cap body and a protective rubber mat, a plurality of anti-skid grooves are evenly formed in the peripheral side of the cap body, the protective rubber mat is tightly arranged on the peripheral side of the cap body in a sleeving mode, and the protective rubber mat is arranged in the anti-skid grooves. The cover body is provided with an anti-skid groove, a pit corresponding to the anti-skid groove is formed in the position of the anti-skid groove, further, the cover body is made of PET resin in an injection molding mode, and the protection rubber mat is formed by mixing natural rubber and ethylene propylene diene monomer rubber and integrally formed with the cover body in an injection molding mode through the double-shot molding technology. According to the plastic bottle cap, due to the fact that the anti-skid grooves in the cap body are matched with the protection rubber mat, the plastic bottle cap can be fully stressed, can be rotated more easily and is not prone to slipping, the soft protection rubber mat can relieve the potential scraping and pressing hand feeling of the hard anti-skid grooves to the hands of a user, and the comfort when the plastic bottle cap is rotated is improved.

Description

Technical Field

[0001] The invention relates to the technical field of plastic bottle caps, and in particular to an anti-slip plastic bottle cap and a preparation method thereof. Background Art

[0002] Plastic bottle caps are one of the most common plastic products in our daily life. Their main function is to seal the bottle and prevent the beverage in the bottle from spoiling. Among them, the rotating plastic bottle cap is the most common. The user can tighten or loosen the bottle cap along the thread by turning it.

[0003] At present, the most common problem with plastic bottle caps when in use is that the bottle caps cannot be twisted. This is generally due to the negative pressure generated inside the bottle. The bottle cap is pressed tightly against the bottle by the atmospheric pressure, which greatly increases the static friction between the bottle cap and the bottle. In addition, the surface roughness of the material of general plastic bottle caps is relatively low, and users are prone to slipping during the actual twisting process, so that the friction generated between the user's fingers and the bottle cap is smaller than the static friction between the bottle cap and the bottle. At this time, the user cannot twist the bottle cap.

[0004] In order to improve the surface roughness of plastic bottle caps and reduce the slippage when users twist the bottle caps, traditional designs are improved from the shape and structure of plastic bottle caps. For example, general mineral water bottle caps add several anti-skid stripes on the outer circumference of the bottle cap to increase the surface roughness of the bottle cap. Although the surface roughness of such plastic bottle caps covered with anti-skid stripes is high, the setting of such anti-skid stripes is generally relatively hard, relatively thin and relatively dense. During long-term storage or transportation, the anti-skid stripes will also be worn or flattened due to external factors such as aging, collision, and extrusion. At this time, not only will users easily slip when twisting, but the anti-skid stripes remaining on the surface will also make people feel uncomfortable and may even produce a small amount of burrs and scratch the fingers of users. Summary of the invention

[0005] In order to improve the anti-slip performance of plastic bottle caps, prolong the anti-slip effect of plastic bottle caps, and improve the touch and comfort of users when turning the plastic bottle caps, the present application provides an anti-slip plastic bottle cap and a preparation method thereof.

[0006] In the first aspect, the present application provides an anti-slip plastic bottle cap adopts the following technical solution: A non-slip plastic bottle cap, comprising a cap body and a protective rubber pad, wherein the inner surface of the cap body is provided with a tightening thread, a plurality of non-slip grooves are evenly opened on the outer peripheral side of the cap body, the protective rubber pad is tightly sleeved on the outer peripheral side of the cap body, and a depression corresponding to the non-slip groove is formed at the position of the non-slip groove; Specifically, the cover body is made of PET resin injection molding, and the protective rubber pad is made of natural rubber and EPDM rubber mixed with each other, and is integrally injection-molded with the cover body through a two-color injection molding process.

[0007] By adopting the above technical solution, the anti-skid grooves on the cover body can provide force application points and mortise and tenon joints for the plastic bottle cap. Not only can the user fully apply force at the position of the anti-skid groove through the protective rubber pad, so that the plastic bottle cap can be fully stressed and easier to rotate, and not prone to slipping, but the protective rubber pad can also be fully mortise and tenon connected with the cover body through the anti-skid groove. When rotating, the protective rubber pad is not easy to slip with the cover body, nor is it easy to fall off the cover body. Secondly, the soft protective rubber pad is coated on the surface of the cover body, which can effectively reduce the potential scratches and rubbing of the harder anti-skid grooves on the user's hands, which is conducive to improving the comfort when rotating the plastic bottle cap. In addition, the cover body and the protective rubber pad are integrally formed through the two-color injection molding process, which is conducive to improving the production efficiency of the plastic bottle cap and reducing the preparation cost.

[0008] Optionally, the cover body (1) is made of the following raw materials in parts by weight: 70-80 parts of PET resin, 20-30 parts of active calcium carbonate, 1.4-1.8 parts of antioxidant, 2.5-3 parts of silane coupling agent, 1.5-2 parts of titanium dioxide, 0.6-0.9 parts of pigments and fillers; The protective rubber pad (2) is made of the following raw materials in parts by weight: 25-30 parts of natural rubber, 20-25 parts of EPDM rubber, 0.5-1 parts of sulfur, 1.2-1.5 parts of vulcanization accelerator, 1.5-2 parts of compatibilizer, 5-8 parts of zinc oxide, 1.5-2 parts of stearic acid, 1.4-1.8 parts of antioxidant, 8-10 parts of modified white carbon black, 0.5-0.75 parts of masterbatch; The modified white carbon black is specifically white carbon black coated with carbonized starch.

[0009] By adopting the above technical solution, it is beneficial to produce a cover body and a protective rubber pad with good heat aging resistance and anti-slip effect.

[0010] Optionally, the preparation of the modified silica used in the raw material of the protective rubber pad (2) includes the following steps: mixing corn starch and water in a weight ratio of 1:(8-10), heating to 80-83°C and continuously stirring and mixing for 20-30 minutes, adding fumed silica after the corn starch forms a paste, wherein the mixing weight ratio of the fumed silica to the corn starch is 1:(0.15-0.2), heating to 84-86°C and continuously stirring for 20-30 minutes, heating to dry the moisture, and then carbonizing it in an inert environment, and then fully crushing it after natural cooling to obtain a carbonized starch-coated modified silica.

[0011] By adopting the above technical scheme, modified silica pre-coated with carbonized corn starch is added as a reinforcing filler of the protective rubber pad, which is not only beneficial to improving the compatibility of modified silica with natural rubber and EPDM rubber and reducing the precipitation of modified silica from the protective rubber pad, but also beneficial to improving the anti-slip performance of the protective rubber pad. When the hands of the user and the plastic bottle cap are kept moist, the surface feel can still have a certain anti-slip effect and is not easy to slip.

[0012] Optionally, the vulcanization accelerator used in the protective rubber pad is a mixture of N-cyclohexyl-2-benzothiazole sulfonamide and 2-mercaptobenzothiazole, and the weight ratio of the N-cyclohexyl-2-benzothiazole sulfonamide to the 2-mercaptobenzothiazole is 1:(0.2-0.5).

[0013] By adopting the above technical scheme, the vulcanization efficiency of the rubber system in which natural rubber and EPDM rubber are mixed with each other can be effectively improved, thereby reducing the pressure holding vulcanization time of the protective rubber pad during the two-color injection molding process, which is beneficial to improving the overall production efficiency of plastic bottle caps.

[0014] Optionally, the antioxidant used in the protective rubber pad is specifically a mixture of antioxidant RD and antioxidant MB in a weight ratio of 1:(0.5-1).

[0015] By adopting the above technical scheme, when antioxidant RD and antioxidant MB are compounded in a weight ratio of 1:(0.5-1), due to the complementary action mechanisms of the two antioxidants, a certain synergistic effect can be produced, which is not only beneficial to improving the aging properties of natural rubber and EPDM rubber such as heat resistance, oxygen, ozone and flexural properties, but also beneficial to preventing fatigue degradation of natural rubber and EPDM rubber, thereby extending the service life of the protective rubber pad.

[0016] Optionally, the color filler used in the cover body is inorganic color powder, and the masterbatch used in the protective rubber pad is specifically made of styrene-butadiene rubber as a carrier and inorganic color powder as a dye.

[0017] By adopting the above technical solution, the inorganic pigment has good light resistance, heat resistance, weather resistance, and solvent resistance. It not only has strong dyeing and covering properties, but also has low migration. Compared with the use of organic pigments, the use of non-toxic inorganic pigments is conducive to improving the long-term color of plastic bottle caps, so that the cap body and protective rubber pad can maintain rich colors for a long time, and can also prevent the cap body and protective rubber pad from fading, color migration, color powder precipitation and other problems.

[0018] Optionally, the tightening thread on the inner surface of the cap body is specifically a right-handed thread that tightens the plastic bottle cap clockwise, and the anti-slip groove is arranged to extend obliquely from top to bottom in a counterclockwise direction.

[0019] By adopting the above technical solution, when the user loosens the plastic bottle cap, the protective rubber pad has a tendency to slide downward along the anti-slip groove. At this time, the user can feel that the protective rubber pad is getting tighter and tighter towards the bottom of the cap body, and it is not easy to fall out. At the same time, the user can also give the cap body a counterclockwise and upward thrust through the protective rubber pad and the anti-slip groove, which is conducive to loosening the plastic bottle cap.

[0020] Optionally, the depth of the anti-slip groove on the cover body is 1-1.2 mm, and the thickness of the protective rubber pad is about 0.8-1 mm.

[0021] By adopting the above technical scheme, the anti-slip groove with a certain depth can provide sufficient force points for the cover body, which is conducive to the cover body being fully stressed and rotated, and the thinner protective rubber pad can not only tightly cover the surface of the cover body, but also form a depression corresponding to the anti-slip groove at the position of the anti-slip groove, which is conducive to the user to fully apply force on the anti-slip groove through the protective rubber pad, but also can reduce the potential scratches and roughness of the harder anti-slip groove on the user's hands to a certain extent, which is conducive to improving the comfort when turning the plastic bottle cap.

[0022] In the second aspect, the present application provides a method for preparing a non-slip plastic bottle cap using the following technical solution: A method for preparing a non-slip plastic bottle cap comprises the following steps: S1, PET resin, activated calcium carbonate, titanium dioxide, antioxidant, silane coupling agent and color filler are fully mixed in proportion, and melt-extruded and granulated after drying to obtain a cover body injection molding material, and then the cover body injection molding material is added to the injection molding machine A of the two-color injection molding machine; natural rubber, EPDM rubber, compatibilizer, zinc oxide, stearic acid, antioxidant, modified white carbon black and masterbatch are fully mixed in proportion, and then extruded and granulated after mixing to obtain a mixed rubber, and then the mixed rubber, sulfur and vulcanization accelerator are fully mixed in proportion to obtain a rubber cushion injection molding material, and then the rubber cushion injection molding material is added to the injection molding machine B of the two-color injection molding machine; S2, firstly perform an injection molding by using the injection molding machine A to inject the molten injection material of the cover into the mold, and then perform a pressure holding and cooling process, and wait until the melt in the mold is basically cooled and shaped to obtain a semi-finished cover; S3, flip the mold, and perform secondary injection molding through injection molding machine B, inject molten rubber pad injection plastic into the mold, and then perform secondary pressure holding and cooling. After the melt in the mold is fully cooled and shaped, open the mold and take out the workpiece from the mold to obtain a non-slip plastic bottle cap.

[0023] By adopting the above technical solution, the cover body and the protective rubber pad are integrally formed using a two-color injection molding process, which can not only reduce the process steps of combining the cover body and the protective rubber pad, but also improve the combination accuracy between the cover body and the protective rubber pad, which is beneficial to improving the molding efficiency of plastic bottle caps and reducing preparation costs.

[0024] Optionally, in step S2, the process parameters of the one-shot injection molding are: mold temperature 120-140° C., melt temperature 270-280° C., injection pressure 140-150 MPa; the process parameters of the one-shot holding pressure are: holding pressure is 75%-80% of the injection pressure, and holding time is 10-15s; In step S3, the process parameters of the secondary injection molding are: mold temperature 80-120°C, melt temperature 190-200°C, injection pressure 140-150MPa; the process parameters of the secondary holding pressure are: holding pressure is 75%-80% of the injection pressure, and holding time is 2.5-3min.

[0025] The adoption of the above technical solution is conducive to producing a cover body and a protective rubber pad with a smooth surface and uniform performance.

[0026] In summary, the technical solution of the present application has at least one of the following beneficial effects.

[0027] 1. The anti-slip grooves on the cover body cooperate with the protective rubber pad, which not only makes the plastic bottle cap fully stressed and easier to turn without slipping, but also the soft protective rubber pad can reduce the potential scratches and rubbing of the user's hands by the harder anti-slip grooves, thereby improving the comfort when turning the plastic bottle cap.

[0028] 2. By adding modified silica pre-coated with carbonized corn starch as a reinforcing filler of the protective rubber pad, it is not only beneficial to reduce the precipitation of modified silica from the protective rubber pad, but also beneficial to improve the anti-slip performance of the protective rubber pad. When the hands of the user and the plastic bottle cap are kept moist, the surface feel can still have a certain anti-slip effect and is not easy to slip.

[0029] 3. The extension direction of the anti-skid groove is set by tightening the right-hand thread, and the anti-skid groove is extended from top to bottom in a counterclockwise direction. When the user loosens the plastic bottle cap, the protective rubber pad has a tendency to slide downward along the anti-skid groove. At this time, the protective rubber pad can be felt to be tightened toward the bottom of the cap body, and is not easy to fall out. At the same time, the user can also give the cap body a counterclockwise and upward thrust through the protective rubber pad and the anti-skid groove, which is conducive to loosening the plastic bottle cap.

[0030] 4. The cover body and the protective rubber pad are integrally formed by adopting a two-color injection molding process, which is beneficial to improving the combination accuracy between the cover body and the protective rubber pad, and is also beneficial to improving the molding efficiency of the plastic bottle cap and reducing the preparation cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 It is a structural schematic diagram of a non-slip plastic bottle cap in Example 1 of the present application.

[0032] Figure 2 It is a cross-sectional view of an anti-slip plastic bottle cap in Example 1 of the present application.

[0033] Figure 3 It is a structural schematic diagram of a plastic bottle cap in Comparative Example 1 of the present application.

[0034] Figure 4 It is a cross-sectional view of a plastic bottle cap in comparative example 1 of the present application.

[0035] Figure 5 It is a structural schematic diagram of a plastic bottle cap in Comparative Example 2 of the present application.

[0036] Figure 6 It is a structural schematic diagram of a plastic bottle cap in Comparative Example 3 of the present application.

[0037] Description of reference numerals: 1. Cover; 11. Tighten the threads; 12. Anti-slip groove; 2. Protective rubber pad. DETAILED DESCRIPTION

[0038] The following is combined with Figure 1-6 , preparation examples, embodiments and comparative examples are further described in detail.

[0039] Preparation Example [Preparation Example 1] A modified white carbon black comprises the following preparation steps: 400g corn starch and water were mixed in a weight ratio of 1:8, heated to 80°C and stirred for 30 minutes, and 2kg fumed silica was added after the corn starch formed a paste. The mixture was heated to 84°C and stirred for 30 minutes. The mixture was further heated to 105°C and the water was dried. The mixture was then placed in an oven at 200°C and carbonized for 6 hours in a nitrogen environment. After it was naturally cooled, it was fully broken to obtain a carbonized starch-coated silica.

[0040] [Preparation Example 2] A modified white carbon black comprises the following preparation steps: 300g corn starch and water were mixed in a weight ratio of 1:10, heated to 83°C and stirred for 20 minutes, and after the corn starch formed a paste, 2kg fumed silica was added, heated to 86°C and stirred for 20 minutes, and then further heated to 105°C and dried to remove moisture, and then placed in an oven at 240°C and carbonized for 3 hours in a nitrogen environment. After cooling naturally, it was fully broken to obtain a carbonized starch-coated silica. Example

[0041] [Example 1] A non-slip plastic bottle cap, referring to Figure 1 and Figure 2 , including a cover body 1 and a protective rubber pad 2. The inner surface of the cover body 1 is provided with a tightening thread 11, and a plurality of anti-skid grooves 12 are evenly opened on the outer peripheral side of the cover body 1. The protective rubber pad 2 is sleeved on the outer peripheral side of the cover body 1 and fits tightly to the outer surface of the anti-skid groove 12. Specifically, in the present embodiment, the tightening thread 11 is a right-handed thread for tightening the plastic bottle cap clockwise, and the anti-skid groove 12 is arranged to extend obliquely from top to bottom in a counterclockwise direction, and the depth of the anti-skid groove 12 is set to 1mm, and the molding thickness of the protective rubber pad 2 is about 0.8mm. Since the protective rubber pad 2 fits tightly to the outer surface of the anti-skid groove 12, a depression corresponding to the anti-skid groove 12 is formed at the position of the anti-skid groove 12.

[0042] In this embodiment, the cover body 1 is made by mixing the following raw materials and injection molding: 8kg PET resin, 2kg activated calcium carbonate, 0.14kg antioxidant, 0.3kg silane coupling agent KH570, 0.2kg titanium dioxide and 0.06kg ultramarine.

[0043] The antioxidant is specifically a mixture of antioxidant 1010 and antioxidant 168 in a weight ratio of 1:1, that is, it contains 0.07 kg of antioxidant 1010 and 0.07 kg of antioxidant 168.

[0044] In this embodiment, the protective rubber pad 2 is made by mixing the following raw materials and injection molding: 3kg natural rubber, 2kg EPDM rubber, 0.08kg sulfur, 0.15kg vulcanization accelerator, 0.2kg compatibilizer, 0.5kg zinc oxide, 0.15kg stearic acid, 0.18kg antioxidant, 1kg modified silica and 0.075kg masterbatch.

[0045] Among them, the vulcanization accelerator is specifically N-cyclohexyl-2-benzothiazole sulfonamide and 2-mercaptobenzothiazole mixed in a weight ratio of 1:0.5, that is, it contains 0.1kg N-cyclohexyl-2-benzothiazole sulfonamide and 0.05kg 2-mercaptobenzothiazole. The compatibilizer is specifically maleic anhydride grafted ethylene propylene rubber. The antioxidant is specifically antioxidant RD and antioxidant MB mixed in a weight ratio of 1:0.5, that is, it contains 0.12kg antioxidant RD and 0.06kg antioxidant MB. The modified silica is specifically selected from a modified silica prepared in [Preparation Example 1]. The masterbatch is specifically selected from a blue masterbatch with SBR as a carrier and ultramarine as a dye.

[0046] A method for preparing a non-slip plastic bottle cap comprises the following steps: S1. Fully mix PET resin, activated calcium carbonate, titanium dioxide, antioxidant, silane coupling agent KH570 and ultramarine in proportion, dry and melt-extrude to granulate, obtain cover body 1 injection plastic, and then add it to injection molding machine A of a two-color injection molding machine; fully mix natural rubber, EPDM rubber, compatibilizer, zinc oxide, stearic acid, antioxidant, modified silica and masterbatch in proportion, and then extrude and granulate to obtain a mixed rubber, then fully mix the mixed rubber, sulfur and vulcanization accelerator in proportion to obtain a rubber pad injection plastic, and then add it to injection molding machine B of a two-color injection molding machine.

[0047] S2. First, perform an injection molding process using the injection molding machine A to inject the molten plastic of the cover body 1 into the mold, wherein the mold temperature is set to 120°C, the melt temperature is 270°C, and the injection pressure is 140MPa. Then, perform a pressure holding and cooling process, wherein the pressure holding pressure is 80% of the injection pressure, the pressure holding time is 10s, and the cooling time is 10s. When the melt in the mold is basically cooled and shaped, a semi-finished product of the cover body 1 is obtained.

[0048] S3, flip the mold, perform secondary injection molding through injection molding machine B, inject molten rubber pad injection plastic into the mold, reduce the mold temperature to 80°C, melt temperature to 190°C, and injection pressure to 120MPa. Then perform secondary pressure holding and cooling, where the pressure holding pressure is 80% of the injection pressure, the pressure holding time is 3 minutes, and the cooling time is 10 seconds. After the melt in the mold is fully cooled and shaped, open the mold and remove the workpiece from the mold to obtain a non-slip plastic bottle cap.

[0049] [Example 2] A non-slip plastic bottle cap, which differs from [Example 1] in that the preparation materials and preparation methods of the cap body 1 and the protective rubber pad 2 are different.

[0050] In this embodiment, the cover body 1 is made by mixing the following raw materials and injection molding: 7kg PET resin, 3kg activated calcium carbonate, 0.2kg antioxidant, 0.25kg silane coupling agent KH570, 0.15kg titanium dioxide and 0.09kg ultramarine.

[0051] The antioxidant is specifically a mixture of antioxidant 1010 and antioxidant 168 in a weight ratio of 1:1.5, that is, it contains 0.08 kg of antioxidant 1010 and 0.12 kg of antioxidant 168.

[0052] In this embodiment, the protective rubber pad 2 is made by mixing the following raw materials and injection molding: 2.5kg natural rubber, 2.5kg EPDM rubber, 0.1kg sulfur, 0.12kg vulcanization accelerator, 0.15kg compatibilizer, 0.8kg zinc oxide, 0.2kg stearic acid, 0.14kg antioxidant, 0.8kg modified silica and 0.05kg masterbatch.

[0053] Among them, the vulcanization accelerator is specifically N-cyclohexyl-2-benzothiazole sulfonamide and 2-mercaptobenzothiazole mixed in a weight ratio of 1:0.2, that is, it contains 0.1kg N-cyclohexyl-2-benzothiazole sulfonamide and 0.02kg 2-mercaptobenzothiazole. The compatibilizer is specifically maleic anhydride grafted ethylene propylene rubber. The antioxidant is specifically antioxidant RD and antioxidant MB mixed in a weight ratio of 1:1, that is, it contains 0.07kg antioxidant RD and 0.07kg antioxidant MB. The modified silica is specifically selected from a modified silica prepared in [Preparation Example 2]. The masterbatch is specifically selected from a blue masterbatch with SBR as a carrier and ultramarine as a dye.

[0054] A method for preparing a non-slip plastic bottle cap, which differs from [Example 1] in that specific parameters during two-color injection molding are different.

[0055] Specifically, in step S2, the process parameters of the first injection molding are: mold temperature is set to 140°C, melt temperature is 280°C, injection pressure is 150MPa. The process parameters of the first holding pressure are: holding pressure is 75% of the injection pressure, holding time is 15s, and cooling time is 10s.

[0056] Specifically, in step S3, the process parameters of the first injection molding are: mold temperature is reduced to 100°C, melt temperature is 200°C, injection pressure is 130MPa. The process parameters of the first holding pressure are: holding pressure is 75% of the injection pressure, holding time is 2.5min, and cooling time is 10s.

[0057] Comparative Example [Comparative Example 1] A plastic bottle cap, referring to Figure 3 and Figure 4, which is different from [Example 1] in that the outer peripheral side of the cover body 1 is not provided with an anti-slip groove 12 .

[0058] [Comparative Example 2] A plastic bottle cap, referring to Figure 5 , which differs from [Example 1] in that the protective rubber pad 2 is not provided.

[0059] [Comparative Example 3] A plastic bottle cap, referring to Figure 6 , which is different from [Example 1] in that the extension direction of the anti-slip groove 12 of the cover body 1 is different.

[0060] In this comparative example, the anti-slip groove 12 extends in the vertical direction.

[0061] [Comparative Example 4] A non-slip plastic bottle cap, which is different from [Example 1] in that the protective rubber pad 2 is made of different materials.

[0062] In this comparative example, no antioxidant is added to the protective rubber pad 2.

[0063] [Comparative Example 5] A non-slip plastic bottle cap, which is different from [Example 1] in that the protective rubber pad 2 is made of different materials.

[0064] In this comparative example, the modified silica in the protective rubber pad 2 is replaced by an equal amount of common fumed silica.

[0065] Performance test data 1. Bottle cap anti-slip feel test: The tester first fully tightens the plastic bottle caps prepared in each embodiment and comparative example on the bottle body corresponding to the plastic bottle cap with a torque force of 3.0 N·m. Then the tester loosens the plastic bottle cap when the plastic bottle cap and both hands are dry or wet, and records the subjective feeling when the plastic bottle caps of each embodiment and comparative example are completely unscrewed.

[0066] 2. Heat aging test of protective rubber pad: firstly, an automatic cycle exposure test is carried out according to the provisions of cycle number 1 of method A in Table 3 of "GB / T 16422.2-2014 Plastic Laboratory Light Source Exposure Test Method", with an exposure time of 1000 hours. The protective rubber pad of the plastic bottle cap should face the side of the xenon lamp light source. After aging, the surface state of the protective rubber pad is observed, and the changes in the appearance and feel of the protective rubber pad of each embodiment and comparative example after xenon lamp aging are recorded.

[0067] According to Example 1 and Comparative Examples 1-2 and combined with the data in Table 1, the anti-skid groove 12 provided on the cover body 1 can provide a force application point and a mortise and tenon joint for the plastic bottle cap. Not only can the user fully apply force at the position of the anti-skid groove 12 through the protective rubber pad 2, so that the plastic bottle cap can be fully stressed and more easily rotated, but the protective rubber pad 2 can also be fully mortise and tenon connected with the cover body 1 through the anti-skid groove 12. When rotating, the protective rubber pad 2 is not easy to slip with the cover body 1, nor is it easy to fall off the cover body 1. Secondly, the soft protective rubber pad 2 is coated on the surface of the cover body 1. When the user rotates the plastic bottle cap, the protective rubber pad 2 can effectively reduce the potential scratches and rubbing of the user's hands by the harder anti-skid groove 12, greatly improving the comfort of rotating the plastic bottle cap.

[0068] According to Example 1 and Comparative Example 3 and combined with the data in Table 1, when the anti-skid groove 12 on the cover body 1 is extended in an inclined direction, the protective rubber pad 2 is less likely to separate from or fall out of the cover body 1 when rotating, compared with when it is extended in a vertical direction. This may be because the plastic bottle caps of Example 1 and Comparative Example 3 both use right-handed threads, that is, the user needs to rotate counterclockwise to loosen the plastic bottle cap, and the anti-skid groove 12 set in Example 1 extends from top to bottom along a counterclockwise tilt, so that when the user is loosening the plastic bottle cap, the protective rubber pad 2 has a tendency to slide downward along the anti-skid groove 12. At this time, the protective rubber pad 2 will feel that it is tightened more and more toward the bottom of the cover body 1, and it is not easy to fall out. At the same time, the user can also give the cover body 1 a thrust in the counterclockwise direction and obliquely upward through the protective rubber pad 2 and the anti-skid groove 12, which is also conducive to loosening the plastic bottle cap. The anti-skid groove 12 in comparative example 3 extends in the vertical direction, and cannot give the protective rubber pad 2 a tendency to slide downward. In addition, when the user loosens the plastic bottle cap, he often applies force to push the plastic bottle cap away from the plastic bottle, so that the protective rubber pad 2 can be felt to fall off the cover body 1 along the anti-skid groove 12.

[0069] According to Example 1 and Comparative Example 4 and combined with the data in Table 1, when an antioxidant is added to the protective rubber pad 2, the heat aging resistance of the protective rubber pad 2 can be effectively improved, and the service life of the protective rubber pad 2 can be extended. The protective rubber pad 2 can also play a certain protective role on the cover body 1 and the anti-slip groove 12 on the cover body 1, and is also conducive to extending the anti-slip effect of the plastic bottle cap.

[0070] According to Example 1 and Comparative Example 5 and combined with the data in Table 1, compared with Example 1, the protective rubber pad 2 to which ordinary fumed silica is added in Comparative Example 5 has a slippery surface feel when the hands of the user and the plastic bottle cap are wet, and is prone to slipping. Moreover, after a long period of aging, a large amount of powder is precipitated on the surface, and the aging effect is not ideal. This may be because the surface of silica has more hydroxyl groups, and the natural rubber and EPDM rubber used as the matrix resin of the protective rubber pad 2 are both non-polar rubbers. The compatibility of ordinary fumed silica with rubber is poor, which is not only easy to separate and precipitate after aging, but also may cause the protective rubber pad 2 to absorb water and form a molecular adsorption layer, reducing the roughness of the surface of the protective rubber pad 2, so that the surface of the protective rubber pad 2 feels relatively slippery. After being coated with corn starch and then carbonized, the surface polarity of the modified silica is greatly reduced, which not only improves the compatibility of the modified silica with rubber and makes it less likely to precipitate after long-term use, but also reduces the water absorption and slippery problems caused by hydroxyl groups, which is beneficial to improving the anti-slip performance of the protective rubber pad 2.

[0071] This specific implementation manner is merely an explanation of the present application and is not a limitation of the present application. After reading this specification, those skilled in the art may make non-creative modifications to the specific implementation manner as needed, but such modifications are protected by the patent law as long as they are within the scope of the claims of the present application.

Claims

1. A non-slip plastic bottle cap, characterized by: It comprises a cover body (1) and a protective rubber pad (2), wherein the inner surface of the cover body (1) is provided with a tightening thread (11), the outer peripheral side of the cover body (1) is evenly provided with a plurality of anti-slip grooves (12), the protective rubber pad (2) is tightly sleeved on the outer peripheral side of the cover body (1), and a depression corresponding to the anti-slip groove (12) is formed at the position of the anti-slip groove (12); Specifically, the cover body (1) is made of PET resin injection molding, and the protective rubber pad (2) is made of natural rubber and EPDM rubber mixed with each other, and is integrally injection molded with the cover body (1) through a two-color injection molding process.

2. The anti-slip plastic bottle cap according to claim 1, characterized in that: The cover body (1) is made of the following raw materials in parts by weight: PET resin 70-80 parts, active calcium carbonate 20-30 parts, antioxidant 1.4-1.8 parts, silane coupling agent 2.5-3 parts, titanium dioxide 1.5-2 parts, color filler 0.6-0.9 parts; The protective rubber pad (2) is made of the following raw materials in parts by weight: 25-30 parts of natural rubber, 20-25 parts of EPDM rubber, 0.5-1 parts of sulfur, 1.2-1.5 parts of vulcanization accelerator, 1.5-2 parts of compatibilizer, 5-8 parts of zinc oxide, 1.5-2 parts of stearic acid, 1.4-1.8 parts of antioxidant, 8-10 parts of modified silica, 0.5-0.75 parts of masterbatch; The modified white carbon black is specifically white carbon black coated with carbonized starch.

3. The anti-slip plastic bottle cap according to claim 2, characterized in that: The preparation of the modified white carbon black used in the raw material of the protective rubber pad (2) comprises the following steps: Corn starch and water are mixed in a weight ratio of 1: (8-10), heated to 80-83°C and continuously stirred for 20-30 minutes, and fumed silica is added after the corn starch forms a paste, wherein the mixing weight ratio of the fumed silica to the corn starch is 1: (0.15-0.2), heated to 84-86°C and continuously stirred for 20-30 minutes, heated to dry the water, and then carbonized in an inert environment, and then fully crushed after naturally cooling to obtain a carbonized starch-coated modified silica.

4. The anti-slip plastic bottle cap according to claim 2, characterized in that: The vulcanization accelerator used in the protective rubber pad (2) is specifically a mixture of N-cyclohexyl-2-benzothiazole sulfenamide and 2-mercaptobenzothiazole, and the weight ratio of the N-cyclohexyl-2-benzothiazole sulfenamide to the 2-mercaptobenzothiazole is 1:(0.2-0.5).

5. The anti-slip plastic bottle cap according to claim 2, characterized in that: The antioxidant used in the protective rubber pad (2) is specifically a mixture of antioxidant RD and antioxidant MB in a weight ratio of 1:(0.5-1).

6. The anti-slip plastic bottle cap according to claim 2, characterized in that: The pigment filler used in the cover body (1) is inorganic pigment powder, and the color masterbatch used in the protective rubber pad (2) is specifically made of styrene-butadiene rubber as a carrier and inorganic pigment powder as a dye.

7. The anti-slip plastic bottle cap according to claim 2, characterized in that: The tightening thread (11) on the inner surface of the cap body (1) is specifically a right-hand thread for tightening the bottle cap in a clockwise direction, and the anti-slip groove (12) is arranged to extend obliquely from top to bottom in a counterclockwise direction.

8. The anti-slip plastic bottle cap according to claim 2, characterized in that: The depth of the anti-slip groove (12) on the cover body (1) is 1-1.2 mm, and the thickness of the protective rubber pad (2) is 0.8-1 mm.

9. The method for preparing a non-slip plastic bottle cap according to any one of claims 2 to 8, characterized in that: The method comprises the following preparation steps: S1, PET resin, activated calcium carbonate, titanium dioxide, antioxidant, silane coupling agent and pigment filler are fully mixed in proportion, and after drying, melt extrusion and granulation are performed to obtain a cover body (1) injection molding material, and then the cover body (1) injection molding material is added to the injection molding machine A of the two-color injection molding machine; natural rubber, EPDM rubber, compatibilizer, zinc oxide, stearic acid, antioxidant, modified white carbon black and masterbatch are fully mixed in proportion, and then extrusion and granulation are performed after mixing to obtain a mixed rubber, and then the mixed rubber, sulfur and vulcanization accelerator are fully mixed in proportion to obtain a rubber pad injection molding material, and then the rubber pad injection molding material is added to the injection molding machine B of the two-color injection molding machine; S2, firstly perform an injection molding process using the injection molding machine A to inject the molten injection material of the cover body (1) into the mold, then perform a pressure holding and cooling process, and wait until the melt in the mold is sufficiently cooled and shaped to obtain a semi-finished cover body (1); S3, flip the mold, and perform secondary injection molding through injection molding machine B, inject molten rubber pad injection plastic into the mold, and then perform secondary pressure holding and cooling. After the melt in the mold is fully cooled and shaped, open the mold and take out the workpiece from the mold to obtain a non-slip plastic bottle cap.

10. The method for preparing a non-slip plastic bottle cap according to claim 9, characterized in that: In step S2, the process parameters of the one-shot injection molding are: mold temperature 120-140°C, melt temperature 270-280°C, injection pressure 140-150MPa; the process parameters of the one-shot holding pressure are: holding pressure is 75%-80% of the injection pressure, and holding time is 10-15s; In step S3, the process parameters of the secondary injection molding are: mold temperature 80-120°C, melt temperature 190-200°C, injection pressure 140-150MPa; the process parameters of the secondary holding pressure are: holding pressure is 75%-80% of the injection pressure, and holding time is 2.5-3min.

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