Polyamide composition as well as preparation method and application thereof

Abstract

The invention relates to a polyamide composition as well as a preparation method and application thereof. The polyamide composition is prepared from the following components in parts by weight: 40 to 90 parts of PA (Polyamide) resin, 0 to 60 parts of glass fiber, 0.5 to 3 parts of nucleating agent, 0.5 to 3.1 parts of PTFE (Polytetrafluoroethylene) resin and 2 to 11 parts of linear low-density polyethylene. The nucleating agent, the PTFE resin and the linear low-density polyethylene are added into the polyamide composition, so that the problem that nozzle casting is easy to occur in the injection molding process of the polyamide material is effectively solved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of high polymer materials, and more particularly to a polyamide composition, a preparation method and application thereof. BACKGROUND

[0002] Polyamide refers to a kind of polymer with repeating amide bonds (-CO-NH-) in the main chain, which is widely used in textile, automobile, electronic and electrical fields.

[0003] However, polyamide material is prone to nozzle sagging during injection molding. Nozzle sagging can cause equipment gate blockage and defects on injection molded parts, causing trouble to the production of enterprises.

[0004] The prior art mainly adjusts the process such as temperature, injection pressure and the like during injection molding to reduce the degree of sagging, but the effect is not good, and the complexity of the injection molding process of the product is increased. SUMMARY

[0005] The primary object of the present application is to overcome the problem of nozzle sagging during injection molding of polyamide material in the prior art, and to provide a polyamide composition.

[0006] A further object of the present application is to provide a preparation method of the above-mentioned polyamide composition.

[0007] A further object of the present application is to provide the use of the above-mentioned polyamide composition in the preparation of sensors and connectors.

[0008] The above-mentioned objects of the present application are achieved by the following technical solutions: A polyamide composition comprises the following components by weight: PA resin 40-90 parts, Glass fiber 0-60 parts, Nucleating agent 0.5-3 parts, PTFE resin (polytetrafluoroethylene resin) 0.5-3.1 parts, Linear low density polyethylene 2-11 parts.

[0009] The present application adds PTFE resin and linear low density polyethylene to the polyamide composition, which cooperatively solves the problem of nozzle sagging during injection molding of polyamide material. The principle may be that PTFE resin can form a fibrous network structure during processing, thereby limiting the flow of the melt; and linear low density polyethylene forms entanglement with PA resin molecules by using the characteristics of short branches and low melting point of its molecular chain, and the two cooperatively alleviate the nozzle sagging during injection molding.

[0010] If LDPE or HDPE is selected instead of linear low density polyethylene, it cannot form good entanglement and cannot effectively solve the problem of injection molding nozzle casting; if too much linear low density polyethylene is added, due to the poor compatibility of linear low density polyethylene and PA resin, the casting problem becomes serious. If too much PTFE resin is added, the casting problem cannot be well solved.

[0011] The present application further adds a nucleating agent, which can promote the crystallization of the melt to alleviate the casting of the melt.

[0012] In the present application, the amount of PA resin can be 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90 parts by weight or a range value formed by any two of the above values; the amount of glass fiber can be 0, 5, 10, 20, 30, 40, 50, 60 parts by weight or a range value formed by any two of the above values; the amount of nucleating agent can be 0.5, 1, 1.5, 2, 2.5, 3 parts by weight or a range value formed by any two of the above values; the amount of PTFE resin can be 0.5, 1, 1.5, 2, 2.5, 3 parts by weight or a range value formed by any two of the above values; the amount of linear low density polyethylene can be 2, 3, 4, 5, 6, 7, 8, 9, 10 parts by weight or a range value formed by any two of the above values.

[0013] In the present application, PA resin is used as the main body resin, which accounts for more than 35wt% of the polyamide composition.

[0014] Preferably, the PA resin is an aliphatic PA resin, including but not limited to at least one of PA6 resin, PA66 resin, PA612 resin and PA610 resin.

[0015] Preferably, the relative viscosity of the PA resin is 1.8-2.8; specifically, it can be 1.8, 2.0, 2.2, 2.4, 2.6, 2.8 or a range value formed by any two of the above values.

[0016] In the present application, the relative viscosity of the PA resin can be measured according to ISO 307-2019 under the condition of 96% concentrated sulfuric acid.

[0017] Preferably, the nucleating agent is at least one of talc, organic polymer salt and lignocenic acid salt.

[0018] More preferably, the organic polymer salt includes but is not limited to polyester sodium salt.

[0019] More preferably, the lignocenic acid salt can be at least one of sodium lignosulfonate and calcium lignosulfonate.

[0020] Preferably, the PTFE resin is in powder form.

[0021] More preferably, the average particle size of the PTFE resin is 200-550 μm; specifically, it can be 200, 250, 280, 290, 300, 320, 350, 380, 400, 450, 480, 500, 520, 550 μm or a range value formed by any two of the above values.

[0022] Further preferably, the average particle size of the PTFE resin is 250-450 μm.

[0023] Further preferably, the average particle size of the PTFE resin is 400-450 μm.

[0024] Controlling the average particle size of the PTFE resin in this range can better solve the problem of nozzle casting.

[0025] In the present application, the average particle size of the PTFE resin can be measured by ISO 13320:2020-light diffraction method.

[0026] Preferably, the mass fraction of the PTFE resin relative to the PA resin is ≤8%; specifically, it can be 0.3%, 0.5%, 1%, 2%, 3%, 5%, 7%, 7.5%, 8%, or a range value formed by any two of the above values.

[0027] Preferably, the linear low-density polyethylene has a melt index of 0.5-13 g / 10 min measured at 190°C under a load of 2.16 kg; specifically, it can be 0.5, 1, 2, 3, 5, 7, 9, 11, 13 g / 10 min or a range value formed by any two of the above values.

[0028] Further preferably, the linear low-density polyethylene has a melt index of 0.8-2 g / 10 min measured at 190°C under a load of 2.16 kg.

[0029] Controlling the melt index of the linear low-density polyethylene in this range can better solve the problem of nozzle casting.

[0030] Preferably, the melt index of the linear low-density polyethylene can be measured by ISO 1133-1-2011.

[0031] Preferably, the linear low-density polyethylene has a melting point of 105-125°C; specifically, it can be 105, 108, 110, 112, 115, 118, 120, 123, 125°C, or a range value formed by any two of the above values.

[0032] In the present application, the melting point of the linear low-density polyethylene can be measured by differential scanning calorimetry (DSC).

[0033] Preferably, the mass fraction of the linear low-density polyethylene relative to the PA resin is ≤25%; specifically, it can be 2%, 5%, 8%, 10%, 12%, 15%, 18%, 20%, 23%, 25% or a range value formed by any two of the above values.

[0034] Preferably, the glass fiber is short-cut glass fiber.

[0035] Preferably, the average diameter of the cross section of the glass fiber is 6-15 μm.

[0036] Preferably, the average length of the glass fiber is 2-6 mm.

[0037] In the present application, the average diameter of the cross section and the average length of the glass fiber can be measured by an optical microscope method.

[0038] Preferably, the polyamide composition further comprises other auxiliary agents in an amount of 0.5-2 parts.

[0039] More preferably, the other auxiliary agent is at least one of an antioxidant and a lubricant.

[0040] Further preferably, the antioxidant is at least one of antioxidant 1010, antioxidant 1098 and antioxidant 168.

[0041] Further preferably, the lubricant is at least one of an ester lubricant, an amide lubricant and an ethylene wax lubricant.

[0042] The preparation method of the polyamide composition comprises the following steps: mixing the components, melt extruding, granulating, and obtaining the polyamide composition.

[0043] Preferably, the temperature of the melt extrusion is 220-280 ℃; the length-diameter ratio of the screw of the extruder for the melt extrusion is 35-50:1, and the rotation speed of the screw is 300-600 r / min.

[0044] The application of the polyamide composition in the preparation of electronic and electrical components and automobile components is also within the protection scope of the present application.

[0045] Preferably, the polyamide composition is applied in the preparation of sensors and connectors.

[0046] A polyamide part is prepared by the polyamide composition.

[0047] Compared with the prior art, the present application has the following beneficial effects: The present application effectively solves the problem of nozzle flow during the injection molding process of the polyamide material by adding a nucleating agent, a PTFE resin and a linear low-density polyethylene to the polyamide composition. DETAILED DESCRIPTION

[0048] In order to more clearly and completely describe the technical solutions of the present application, the present application is further described in detail below through specific examples. It should be understood that the specific examples described herein are only used to explain the present application and are not used to limit the present application, and various changes can be made within the scope of the present application.

[0049] Some reagents selected for the embodiments and comparative examples of the present application are described as follows: PA resin 1#: PA6, Xinhuaimida, M2400, relative viscosity 2.4; PA resin 2#: PA6, Xinhuaimida, M2000, relative viscosity 2.0; PA resin 3#: PA66, Yingweida, U3600, relative viscosity 2.4; Glass fiber: China Jushi, ECS10-03-568H, chopped glass fiber; Nucleating agent 1#: talc powder, Imifabi, Ultra5L; Nucleating agent 2#: mixture of polyester sodium salt and talc powder, Brüggemann, P22; Nucleating agent 3#: sodium lignosulfonate, Licomont NAV101, Clariant; PTFE resin 1#: CHEMOURS, 6CN X, average particle size 400 μm; PTFE resin 2#: StargetFluro, PTFE 102, average particle size 250 μm after screening; PTFE resin 3#: CHEMOURS, 602 X, average particle size 550 μm; PTFE resin 4#: CHEMOURS, 669 X, average particle size 450 μm; Linear low density polyethylene (LLDPE) 1#: melt index 1 g / 10 min, ExxonMobil, C4LL 1018.AN; Linear low density polyethylene 2#: melt index 0.8 g / 10 min, ExxonMobil, C6LL 0825.15; Linear low density polyethylene 3#: melt index 12 g / 10 min, ExxonMobil, C4LL 12026.19; Low density polyethylene (LDPE) 1#: melt index 2 g / 10 min, ExxonMobil, LD 2023.BW; High density polyethylene (HDPE) 1#: melt index 4 g / 10 min, ExxonMobil, HD 6040.UV; Other auxiliary 1: Antioxidant 1098, antioxidant, commercially available; As no specific description, each component (such as glass fiber, other auxiliary 1) selected in each parallel example and comparative example is the same commercially available product.

[0050] The polyamide composition of the embodiments and comparative examples of the present application is prepared by the following preparation method: (1) According to the proportion, each component is weighed and put into a high-speed mixer, mixed uniformly to obtain a mixture.

[0051] (2) The mixture is put into a twin-screw extruder, and the temperature of the extruder is set according to the temperature of each zone in the order of 220℃, 240℃, 245℃, 250℃, 260℃, 270℃, 280℃, 275℃, 265℃, 240℃, the rotation speed is 500r / min, and the screw length-diameter ratio is 40:1; After mixing, melting and homogenization, the polyamide composition is prepared by extrusion and granulation.

[0052] The polyamide composition provided by each embodiment and comparative example of the present application is tested according to the following test method: Nozzle casting: The temperature range of the injection molding machine is set to 220~280℃, the injection pressure is 50%, the injection speed is 50%, and the back pressure is 5bar. Under the above conditions, manual operation mode is carried out, once complete storage is carried out, no ejection process is carried out after storage, then the nozzle is cleaned, and the timing is started again after cleaning, the time is 10min, the melt flowing out of the nozzle is collected, and after cooling, it is weighed.

[0053] Examples 1~12 Examples 1~12 provide a series of polyamide compositions, and the formula is shown in Table 1.

[0054] Table 1 Formula of Examples 1~12 (parts by weight) .

[0056] Comparative examples 1~9 Comparative examples 1~9 provide a series of polyamide compositions, and the formula is shown in Table 2.

[0057] Table 2 Formula of Comparative examples 1~9 (parts by weight) .

[0059] The performance of the polyamide composition of each embodiment and comparative example is tested according to the above-mentioned test method, and the test results are shown in Table 3.

[0060] Table 3 Performance test results of polyamide composition of each embodiment and comparative example .

[0062] From Table 3, it can be seen that: The mass of the collected fluid in the nozzle die test of the polyamide compositions of Examples 1 to 12 is not higher than 16 g, indicating that the polyamide compositions of the present application can well avoid the die drool problem occurring in the injection molding process.

[0063] Comparative Example 1 does not add nucleating agent, and the polyamide composition fails to well avoid the die drool problem occurring in the injection molding process.

[0064] Comparative Example 2 does not add PTFE resin, and the polyamide composition has a serious die drool problem in the injection molding process.

[0065] Comparative Example 3 does not add LLDPE, and the polyamide composition has a serious die drool problem in the injection molding process.

[0066] Comparative Example 4 does not add PTFE resin, and uses an equal amount of LLDPE instead, and the polyamide composition fails to well avoid the die drool problem occurring in the injection molding process.

[0067] Comparative Example 5 does not add LLDPE, and uses an equal amount of PTFE instead, and the polyamide composition has a serious die drool problem in the injection molding process.

[0068] Comparative Example 6 uses LDPE instead of LLDPE, and the polyamide composition fails to well avoid the die drool problem occurring in the injection molding process.

[0069] Comparative Example 7 uses HDPE instead of LLDPE, and the polyamide composition has a serious die drool problem in the injection molding process.

[0070] Comparative Example 8 adds too much LLDPE, and the polyamide composition has a serious die drool problem in the injection molding process.

[0071] Comparative Example 9 adds too much PTFE resin, and the polyamide composition fails to well avoid the die drool problem occurring in the injection molding process.

[0072] Obviously, the above embodiments of the present application are merely exemplary and are not intended to limit the embodiments of the present application. Based on the above description, other different forms of changes or variations can be made by those skilled in the art. It is not necessary or possible to exhaust all the embodiments. Any modification, equivalent replacement and improvement made within the spirit and principle of the present application shall be included in the protection scope of the claims of the present application.

Claims

1. A polyamide composition, characterized in that, The components include the following parts by weight: 40-90 parts of PA resin, 0-60 parts glass fiber Nucleating agent 0.5-3 parts, 0.5~3.1 parts of PTFE resin, 2 to 11 parts of linear low-density polyethylene.

2. The polyamide composition according to claim 1, characterized in that, The PA resin is an aliphatic PA resin; preferably, the aliphatic PA resin is at least one of PA6 resin, PA66 resin, PA612 resin and PA610 resin.

3. The polyamide composition according to claim 1, characterized in that, The relative viscosity of the PA resin is 1.8 to 2.

8.

4. The polyamide composition according to claim 1, characterized in that, The nucleating agent is at least one of talc, organic polymer salt, and lignite.

5. The polyamide composition according to claim 1, characterized in that, The PTFE resin is in powder form; preferably, the average particle size of the PTFE resin is 200~550μm.

6. The polyamide composition according to claim 1, characterized in that, The melt flow index of the linear low-density polyethylene measured at 190°C and 2.16 kg was 0.5~13 g / 10 min.

7. The polyamide composition according to claim 1, characterized in that, The polyamide composition also includes 0.5 to 2 parts of other additives.

8. A method for preparing the polyamide composition according to any one of claims 1 to 7, characterized in that, The process includes the following steps: mixing the components, melt extruding, and granulating to obtain the polyamide composition.

9. The use of the polyamide composition according to any one of claims 1 to 7 in the preparation of electronic and electrical components and automotive parts.

10. A polyamide component, characterized in that, It is prepared by any of the polyamide compositions according to claims 1 to 7.