CN1903912A - Material for making toothbrush bristle and its preparation method - Google Patents

Abstract

The invention discloses a material for toothbrush filaments and a preparation method thereof. The present invention introduces a long carbon chain nylon segment with a very low water absorption rate into the ordinary nylon by adding a long carbon chain nylon resin when the ordinary nylon (nylon 6, nylon 66) is polymerized, and using an amide group exchange reaction; The polyamide copolymerized group and the monomer of the hydrophobic group are used to cap the polyamide; a nucleating agent is added to improve the crystallinity of nylon. The 48h saturated water absorption of ordinary nylon is reduced from 7% to 2% or lower. In addition, the molding shrinkage of ordinary nylon is improved, and the good wear resistance and elastic recovery of nylon are maintained. Its modulus is equivalent to that of nylon 612, which ensures that the taste and function of its brush filaments are the same as those of nylon 612 brush filaments under the condition of the same filament diameter.

Description

A kind of material for toothbrush filament and preparation method thereof

technical field

The invention relates to a toothbrush silk material, in particular to a nylon copolymer used for a toothbrush and a synthesis method thereof.

Background technique

Toothbrush is an inseparable tool in our daily life. A good toothbrush head can not only clean teeth, but also not damage the oral cavity, increasing the fun of brushing teeth.

With the improvement of living standards, people have higher and higher requirements for toothbrush heads, which require wear resistance, good resilience, moderate hardness and good taste. This has higher and higher requirements on the brush wire material of the toothbrush head. The filament materials on the toothbrush head are mainly polypropylene, polyester and nylon. Among them, polypropylene can only be used as low-grade toothbrush filaments due to its poor wear resistance and resilience, while polyester has disadvantages such as large size deviation and low straightness in spinning due to its large molding shrinkage, especially in the case of small filament diameters. Under the circumstances, its shortcoming becomes more and more obvious, and it is difficult to meet the development direction of toothbrush filaments to ultrafine and wear-resistant. Although ordinary nylon such as nylon 6 has good wear resistance and elastic recovery, it is easy to absorb water. Because water has a plasticizing effect on nylon, nylon 6 brush filaments are prone to permanent deformation in a humid environment and cannot be used for a long time. Nylon 612 is not only wear-resistant and has excellent elastic recovery, but also has low water absorption and good dimensional stability, especially its moderate modulus. The brush filaments have a good taste and sufficient rigidity to remove impurities in the teeth. Therefore, it is often used as a high-grade toothbrush filament material. However, its price is expensive, which limits the scope of use, and can only be used for high-grade toothbrushes and some special occasions, such as scrubbing under harsh working conditions.

In view of the shortcomings of the above brush filament materials, there are many studies hoping to improve the above shortcomings through material modification and obtain more ideal brush filament materials. These studies mainly focus on nylon modification. One is to add fluorine-containing monomers or organosilicon monomers during nylon polymerization through copolymerization to introduce hydrophobic groups to reduce the water absorption of ordinary nylon; the other is to make nylon and polyester into skin cores through special processes Combining the advantages of the two monofilaments, a brush filament material with excellent performance can be obtained. As far as the first method is concerned, the addition of monomers containing hydrophobic groups during polymerization has two effects on the water absorption of nylon. On the one hand, the introduction of hydrophobic groups is beneficial to reduce the water absorption of nylon. On the other hand, the copolymerization of comonomers and nylon will destroy the regularity of nylon and reduce the probability of crystallization of amide groups, while the water absorption of non-crystallized amide groups more capable. Therefore, the effect of improving the water absorption performance of nylon by this method is limited. In addition, the addition of comonomer will greatly reduce the modulus of nylon. For the second method, the process is complicated and the requirements for equipment are also very high.

Contents of the invention

The technical problem to be solved in the present invention is to disclose a material for toothbrush filaments and a preparation method thereof, so as to overcome the defects in the prior art and meet people's needs.

Technical concept of the present invention is such:

The present invention introduces a long carbon chain nylon segment with a very low water absorption rate into the ordinary nylon by adding a long carbon chain nylon resin when the ordinary nylon (nylon 6, nylon 66) is polymerized, and using an amide group exchange reaction; The polyamide copolymerized group (such as amino group, carboxyl group, hydroxyl group, etc.) and the monomer of the hydrophobic group cap the polyamide; add a nucleating agent to improve the crystallinity of nylon. Through the above measures, the purpose of reducing the water absorption of nylon is achieved.

Method of the present invention comprises the steps:

Polymerize nylon monomers, long carbon chain nylon resins, monomers containing a single group that can be copolymerized with polyamide and a hydrophobic group, and a nucleating agent. Polymerize for 0.3 to 18 hours, then reduce the pressure to -0.1 to 0 MPa, polycondensate for 0.3 to 24 hours, and then discharge and cut into pellets to obtain the material for toothbrush filaments of the present invention;

The nylon monomer is selected from nylon monomers selected from caprolactam or nylon 66;

The long carbon chain nylon resin is selected from one of nylon 9, nylon 11, nylon 12, nylon 1212 or nylon 1010;

The weight ratio of the long carbon chain nylon resin to the nylon monomer is 2 to 35:100;

The monomer containing a single group and a hydrophobic group that can be copolymerized with polyamide is selected from amino silicone oils, such as Dow Corning's 8460, 8822, 8209, General Electric's TSF4703, Rhone-Planck's 21637, 21642; one of Nikka Silicone AM of Rihua Company, WR 1300 and WT1650 of Wake Company, based on the weight of nylon monomer, the addition amount is 0.1-5wt.%.

The nucleating agent is selected from silicon dioxide, molybdenum disulfide, titanium dioxide, talcum powder, or iron sulfide, and the addition amount is 0.1-9wt.‰ based on the weight of nylon monomer;

The performance of the obtained nylon is close to that of nylon 612, and it is an ideal brush material, and the cost is far cheaper than that of nylon 612. Since the modified material is mainly long carbon chain nylon resin, and through amide group exchange, long carbon chain nylon segments with multiple repeating units are introduced into ordinary nylon, which is better than random copolymerization between monomers. It improves the regularity of the nylon structure; and has the function of the end-capping of the hydrophobic group and the nucleating agent to improve the crystallinity; therefore, it can effectively improve the water absorption of ordinary nylon. The 48h saturated water absorption of ordinary nylon is reduced from 7% to 2% or lower. In addition, the molding shrinkage of ordinary nylon is improved, and the good wear resistance and elastic recovery of nylon are maintained. Its modulus is equivalent to that of nylon 612, which ensures that the taste and function of its brush filaments are the same as those of nylon 612 brush filaments under the condition of the same filament diameter. Its brush performance is as follows: Test items Wire diameter mm Deviation mm Tensile strength/MPa rebound rate value 0.1 ±0.005 700 ≥100%

Detailed ways

The test of product performance is carried out by the method stipulated in GB standard.

Example 1

Polymerize 90 kg of caprolactam, 10 kg of raw nylon 9 resin, 1 kg of TSF4703 amino silicone oil from General Electric Company and 0.9 kg of nucleating agent silica, first polymerize at 200 °C and 0.2 MPa for 5 hours, and then depressurize to - 0.1MPa, continue to polymerize for 3 hours, the material for toothbrush filament of the present invention is obtained, the material is extruded and pelletized, and can be sent to a fiber production plant for the manufacture of toothbrush filament material.

The product properties obtained are as follows: Test items Molding shrinkage/% Tensile strength/MPa Elongation at break/% Tensile modulus/% Bending strength/MPa Spring rate wire diameter 0.1mm Water absorption/water 48h/% value 1.1 62 300 2000 56 ≥100% 2

Example 2

Polymerize 93 kg of nylon 66 salt, 7 kg of nylon 11 resin, 0.5 kg of Dow Corning's 8460 amino silicone oil and 0.1 kg of nucleating agent talcum powder, first polymerize at 230 ° C and 5 MPa for 12 hours, and then reduce the pressure to -0.1 MPa , continue to polymerize for 9 hours, promptly obtain the material for toothbrush filament of the present invention, extrude material and pelletize, can send fiber production plant to carry out the manufacture of toothbrush filament material. The properties of the materials are shown in the table below. Test items Molding shrinkage/% Tensile strength/MPa Elongation at break/% Tensile modulus/% Bending strength/MPa Spring rate wire diameter 0.1mm Water absorption/water 48h/% value 1.0 60 300 1950 54 ≥100% 2

Example 3

Polymerize 65 kg of caprolactam, 35 kg of nylon 1212 resin, 1 kg of Dow Corning’s 8460 amino silicone oil and 0.05 kg of nucleating agent titanium dioxide, first polymerize at 260 °C and 10 MPa for 24 hours, then reduce the pressure to -0.1 MPa, and continue the polymerization After 12 hours, the material for toothbrush filaments of the present invention is obtained, and the material is extruded and pelletized, and then sent to a fiber production plant for the manufacture of toothbrush filament materials. The properties of the materials are shown in the table below. Test items Molding shrinkage/% Tensile strength/MPa Elongation at break/% Tensile modulus/% Bending strength/MPa Spring rate wire diameter 0.1mm Water absorption/water 48h/% value 1.0 62 300 2000 56 ≥100% 2

Example 4

Polymerize 75 kg of nylon 66 salt, 25 kg of nylon 1010 resin, 1 kg of Dow Corning's 8460 amino silicone oil and 0.1 kg of nucleating agent titanium dioxide, first polymerize at 240 ° C and 7 MPa for 18 hours, and then reduce the pressure to -0.1 MPa, After continuing to polymerize for 7 hours, the material for toothbrush filaments of the present invention is obtained, and the material is extruded and pelletized, and then sent to a fiber production plant for the manufacture of toothbrush filament materials. The properties of the materials are shown in the table below. Test items Molding shrinkage/% Tensile strength/MPa Elongation at break/% Tensile modulus/% Bending strength/MPa Spring rate wire diameter 0.1mm Water absorption/water 48h/% value 1.0 59 300 1750 52 ≥100% 2

Example 5

85 kg of nylon 66 salt, 15 kg of nylon 11 resin, 0.5 kg of Dow Corning's 8209 amino silicone oil and 0.08 kg of nucleating agent molybdenum disulfide were polymerized, first polymerized at 240 ° C and 5 MPa for 18 hours, and then reduced to -0.1 MPa, continue to polymerize for 7 hours to obtain the material for toothbrush filaments of the present invention, extrude the material into pellets, and then send it to a fiber production plant for the manufacture of toothbrush filament materials. The properties of the materials are shown in the table below. Test items Molding shrinkage/% Tensile strength/MPa Elongation at break/% Tensile modulus/% Bending strength/MPa Spring rate wire diameter 0.1mm Water absorption/water 48h/% value 1.0 57 300 1700 50 ≥100% 2

Claims (6)

1. a preparation method for the material of toothbrush silk, it is characterized in that, comprises the steps: with nylon monomer, long carbon chain nylon resin, containing single group and hydrophobic group that can be copolymerized with polyamide body and nucleating agent for polymerization, the polymerization temperature is 200-280°C, the polymerization pressure is 0.2MPa-10MPa, then the pressure is reduced to -0.1-0MPa, the polymerization time is 0.3-24 hours, and finally the material is discharged and pelletized to obtain the The material of the toothbrush filament; The nylon monomer is selected from caprolactam or nylon 66. 2. The method according to claim 1, characterized in that said long carbon chain nylon resin is selected from nylon 9, nylon 11, nylon 12, nylon 1212 or nylon 1010. 3. The method according to claim 1, characterized in that the weight ratio of the nylon monomer to the long carbon chain nylon resin is 2 to 35:100. 4. The method according to claim 1, characterized in that, the monomer containing a single group and a hydrophobic group that can be copolymerized with polyamide is selected from amino silicone oil, and in terms of the weight of nylon monomer, add The amount is 0.1-5 wt.%. 5. method according to claim 1, is characterized in that, said nucleating agent is selected from silicon dioxide, molybdenum disulfide, titanium dioxide, talcum powder or iron sulfide, by the weight of nylon monomer, add-on 0.1-9wt.‰. 6. A material for toothbrush filaments prepared according to any one of claims 1 to 5.