CN115304504A

CN115304504A - Environment-friendly cable and manufacturing process thereof

Info

Publication number: CN115304504A
Application number: CN202210899619.5A
Authority: CN
Inventors: 陈建新; 吴伟; 潘秀
Original assignee: Wuhan Wuhu Cable Co ltd
Current assignee: Wuhan Wuhu Cable Co ltd
Priority date: 2022-07-28
Filing date: 2022-07-28
Publication date: 2022-11-08
Anticipated expiration: 2042-07-28
Also published as: CN115304504B

Abstract

The invention relates to an environment-friendly cable and a manufacturing process thereof. The application discloses a novel PVC plasticizer 2-amino-3- (naphthalene-2-yl) octyl propionate for the first time, discloses a preparation process thereof, and prepares an environment-friendly PVC cable material and a cable by using the novel PVC plasticizer as the novel environment-friendly PVC plasticizer. Compared with the PVC cable taking DOTP as the plasticizer, the performance evaluation shows no significant difference. But avoids the use of phthalate plasticizers.

Description

Environment-friendly cable and manufacturing process thereof

Technical Field

The invention belongs to the field of cables, and particularly relates to an environment-friendly cable and a manufacturing process thereof.

Background

Polyvinyl chloride (PVC) is a chlorine-containing polymer, one of the most widely used plastics in the world, and has low price, excellent corrosion resistance and electrical insulation, especially flame-retardant and self-extinguishing resistance, so that the PVC has been widely used in the production of cable materials, has a long-term important role in the insulation and protection materials of wires and cables, and is widely used as the insulation and protection materials of various wires and cables.

However, polyvinyl chloride has many disadvantages. The first is the environmental problem. The polyvinyl chloride cable material contains chlorine element, so the polyvinyl chloride cable material has good flame retardant property, but generates hydrogen chloride gas and a large amount of black smoke during combustion, thereby causing great harm to human bodies and causing secondary disaster of cable combustion. Secondly, the traditional formula of the polyvinyl chloride cable material contains substances such as heavy metals and harmful plasticizers which are harmful to human bodies, and the polyvinyl chloride cable material also has great harm to the surrounding environment.

Under the current economic and social development situation, the attention of people to health and environmental problems is continuously increased. Strict environmental standards and regulations have also been set by many countries that regulate emissions of harmful pollutants, with typical regulations including RoHS (directive on the restriction of the use of certain harmful components in electrical and electronic equipment) and REACH (registration, evaluation, approval and restriction of chemicals).

The polyvinyl chloride resin has a plurality of defects, the cable material directly prepared cannot meet the performance requirement, and a plurality of additives are required to be added to improve the performance. The additives mainly added in the formula of the polyvinyl chloride cable material comprise a flame retardant, a heat stabilizer, a plasticizer, a filler, a lubricant and the like.

Inorganic flame-retardant materials are added into high molecular materials used for manufacturing cable insulation and outer protective layers, for example, flame retardants such as aluminum hydroxide and magnesium hydroxide are added to improve the flame retardant property of the materials, but the addition of the fillers is limited, the electrical property and the mechanical property of the cable can be reduced by adding the fillers, and if the fillers are added too much, the electrical property and the mechanical property of the cable can not meet the use requirements. In spite of these inorganic fillers, the cable still burns and emits harmful substances under the condition of flame, and thus, the generation of pollutants caused by the cable burning should be avoided as much as possible.

PVC is extremely heat-sensitive and extremely easy to be thermally degraded, and can be decomposed to generate hydrogen chloride at the temperature of more than 100 ℃ or after being exposed to sunlight for a long time, and the hydrogen chloride is further automatically catalyzed and decomposed to cause color change, and the physical and mechanical properties are also rapidly reduced, so that a stabilizer must be added in practical application to improve the stability to heat and light.

The factors that cause PVC degradation are broadly divided into two major categories, structural and environmental. Most of PVC circulating in the market is produced by free radical suspension polymerization or free radical bulk polymerization, and because the prior technical means cannot perfectly control the polymerization reaction and inhibit the side reaction, some uncontrollable structures are generated in the polymerization reaction, and the structures are the fundamental factors for instability of PVC. In the polymerization process of vinyl chloride, HCI removal reaction or oxidation reaction and the like which are not determined to occur can cause some flaws to the normal PVC molecular chain structure, namely abnormal structures in the PVC molecular chain. These abnormal structures mainly include branched structures, unsaturated terminal group structures, chlorine-rich structures, allyl chloride structures, and the like. The abnormal structures, especially the allyl chloride structure and the tertiary chloride structure, can remove hydrogen chloride under the action of variable external conditions, further decompose PVC, and the removed hydrogen chloride can catalyze the decomposition of PVC materials, so that the materials slowly change color, the performance is reduced, and the application value is lost.

The polyvinyl chloride molecule destruction process has the following mechanism: thermal oxidation decomposition; free radical crosslinking in the absence of oxygen; the influence of stereoregularity on degradation; carrying out photodegradation; oxidizing to remove HCl; radiation degradation; molecular chain breakage caused by critical stress introduced in the processing process; and the influence of the branching point in the polyvinyl chloride molecule on degradation, and the like.

In order to make up for the serious drawbacks of polyvinyl chloride homopolymers and copolymers to the maximum extent, it is necessary to eliminate the unstable sites which cause the onset of HCl elimination with stabilizers; or as a scavenger of HCl; or reacts with free radicals as they are generated; or as an antioxidant; or the polyene structure is altered to prevent color change, molecular chain scission, and crosslinking. The stabilizer must be compatible with the polyvinyl chloride system, not detracting from the aesthetics of the material system as a whole, and should also have lubricating properties.

At present, PVC heat stabilizers are in various types, generally classified according to the chemical components of the heat stabilizer, and can be classified into basic lead salts, metal soaps, organic tin, epoxy compounds, phosphite esters, polyhydric alcohols and the like. Because the single heat stabilizer is added, the heat stability of PVC can hardly meet the requirement, and the PVC heat stabilizer is divided into a main heat stabilizer and an auxiliary heat stabilizer according to the action.

The primary heat stabilizer is generally a metal salt heat stabilizer; the secondary heat stabilizer has little or no heat stabilization effect by itself, but has a synergistic effect when used with the primary stabilizer. In the current mainstream environment-friendly PVC heat stabilizer formula system, the beta-diketone compound is a commonly used auxiliary heat stabilizer, and is usually matched with a metal soap type main heat stabilizer for use, so that the heat stability of PVC can be effectively improved.

The main purpose of using the filler is to reduce the cost of the cable material and to improve certain properties of the cable material, such as electrical insulation property, mechanical property and the like. Common polyvinyl chloride fillers include calcium carbonate, calcined china clay, white carbon black, and the like.

Calcium carbonate is the most commonly used inorganic powdered filler and can be classified into heavy calcium carbonate, light calcium carbonate and colloidal calcium carbonate.

The calcined pottery clay has high hardness, larger particle volume, small specific area and low thermal expansion coefficient. In addition, calcined china clay has excellent electrical properties.

The white carbon black is silicon dioxide, so that the insulating property is good, the pores are formed, the internal surface area is large, and the reinforcing effect is obvious.

The polyvinyl chloride cable material uses ground calcium carbonate as filler.

The lubricant is an essential aid in the processing process of polyvinyl chloride, and mainly has the functions of reducing the abrasion between a polyvinyl chloride material and a processing machine and reducing the mutual friction among molecules in the polyvinyl chloride.

The lubricants are therefore divided into external lubricants and internal lubricants. Generally, internal lubricants are based on polar molecules, completely soluble in polyvinyl chloride, such as glyceryl monostearate; external lubricants are generally non-polar and have little compatibility with polyvinyl chloride, such as paraffin wax. Besides, the lubricant can be used in cable materials to resist static and blocking, improve appearance and gloss of products and the like. Commonly used lubricants can be classified into saturated hydrocarbons, fatty acids, fatty acid esters, metallic soaps, alcohols, and the like, according to their chemical structure.

Hydrocarbon lubricants are excellent external lubricants and are environmentally friendly and non-toxic, but most hydrocarbon lubricants have poor compatibility with polyvinyl chloride and poor thermal stability, and are therefore not ideal internal lubricants and cannot be used in excess in cable materials. Liquid paraffin, natural paraffin, microcrystalline paraffin, polyethylene wax and other hydrocarbon paraffin and mineral oil are typical hydrocarbon lubricants.

Many of the fatty acid-based lubricants used in polyvinyl chloride are refined products of fatty acids, including saturated fatty acids, unsaturated fatty acids, and hydroxy fatty acids, but mainly higher saturated fatty acids and those having 12 or more carbon atoms can be used as the lubricant. Stearic acid is most widely used, the pure product of the stearic acid is glossy white soft small pieces, the melting point of the stearic acid is 70-71 ℃, the stearic acid can be dissolved in ethanol and propanol but is hardly dissolved in water, and the stearic acid is also a main raw material for producing the fatty acid derivative lubricant. Fatty acid lubricants have excellent external lubricating properties and are often used in combination with other internal lubricants.

The fatty acid esters used as the lubricant are higher fatty acid esters including lower alcohol esters of fatty acids, ester waxes, polyhydric esters, polyethylene glycol esters, and the like. Because the ester group has polarity and strong affinity to polyvinyl chloride molecules, the fatty acid ester lubricant has good compatibility with polyvinyl chloride and excellent internal lubricating property. It is often used in combination with a heat stabilizer such as a metal soap or an organic tin.

The alcohol compound used as the lubricant is mainly a saturated aliphatic alcohol having 16 or more carbon atoms, and has a relatively high melting point. The alcohol lubricant, especially higher alcohol, has good compatibility with polyvinyl chloride, excellent internal lubricating performance and better effect when being matched with heat stabilizers such as metal soap, organic tin and the like.

The polyvinyl chloride resin has stronger polarity, larger intermolecular force and poorer molecular chain mobility, so the glass transition temperature is higher, the processing performance is poorer and the molding is difficult. After a proper amount of plasticizer is added into the formula, molecules of the plasticizer can be inserted into the middle of polyvinyl chloride molecules, so that the distance between polyvinyl chloride molecules is increased, the intermolecular force is weakened, the viscosity and the plasticizing temperature of polyvinyl chloride plastisol are reduced, the polyvinyl chloride resin is easier to process, and the product quality is better.

The plasticizer is generally a high boiling point, relatively nonvolatile liquid or low melting point solid, and is mostly an ester organic compound. The plasticizer is used as an auxiliary agent in the largest amount in PVC products, and plays an important role in improving the application performance of PVC, particularly soft products of PVC. Plasticizers for PVC are reported to account for about 90% of the total plasticizer. The plasticizers most commonly used in the industrial production of PVC cables today include: dioctyl phthalate (DOP), diisodecyl phthalate (DIDP), dioctyl terephthalate (DOTP), trioctyl trimellitate (TOTM), epoxidized Soybean Oil (ESO), etc.,

the usage amount of the phthalate plasticizer reaches millions of tons worldwide every year, and accounts for more than 80% of the total amount of the plasticizer, wherein DOP is widely used by merchants due to low price, high plasticizing efficiency and good comprehensive performance, and the annual usage amount accounts for 70% of phthalate. However, such plasticizers tend to migrate in PVC cables, for example: is extracted by the solvent and has the phenomenon of heating and volatilization, and can pollute the environment and damage the human health in the process. The influence of phthalate plasticizers on animals is comprehensively analyzed and researched by scholars in various countries, and the influences on the incidence rate of liver cancer of rats and physiological functions of reproduction, development, endocrine regulation and the like of the rats are found, so that the phthalate plasticizers are considered to be harmful to human bodies.

For environmental protection purposes, many developed countries have different levels of restrictions on phthalate plasticizers. For example, the European Union has issued directive 2005/84/EC in 2005, with many industries banning phthalate plasticizers. Subsequently, similar statutes were also successively issued in countries such as the united states, japan, sweden, and the like. With the improvement of environmental protection requirements of China on various industries and the enhancement of health and environmental protection awareness in society, the environment-friendly plasticizer is more and more concerned by various social circles, and the development of novel nontoxic green products with excellent performance becomes the development trend of the plasticizer.

Disclosure of Invention

The applicant has conducted extensive research on PVC cable materials as a cable and related technology development and production enterprise.

Firstly, the invention provides a novel environment-friendly PVC plasticizer which is used for production and processing of PVC cable materials and can replace phthalate plasticizers. The novel PVC plasticizer is 2-amino-3- (naphthalene-2-yl) octyl propionate, and has the following chemical structure:

next, a method for preparing the plasticizer is provided, which comprises the following steps:

step 1: dissolving 2-amino-3- (naphthalene-2-yl) propionic acid and n-octanol in dioxane, and esterifying at room temperature in the presence of concentrated hydrochloric acid as catalyst;

step 2: and (2) adding diethyl ether into the reaction mixture obtained in the step (1), filtering a precipitate, and washing to obtain a final reaction product, namely the 2-amino-3- (naphthalene-2-yl) octyl propionate.

Thirdly, the application discloses a PVC cable material taking 2-amino-3- (naphthalene-2-yl) octyl propionate as a plasticizer, and the formula is as follows according to mass percent:

PVC：40%-60%；

plasticizer: 15 to 30 percent;

a stabilizer: 1 to 3 percent;

flame retardant: 15 to 30 percent;

inorganic filler: 5 to 15 percent;

and (3) the rest auxiliary agents: 1 to 3 percent.

The plasticizer is 2-amino-3- (naphthalene-2-yl) octyl propionate.

The stabilizer is one or more of lead salt stabilizer, composite stabilizer, organic tin stabilizer and metal soap stabilizer;

the flame retardant is one or more of antimony trioxide, zinc borate, zinc stannate, molybdenum trioxide, basic magnesium carbonate, tricresyl phosphate and tetrabromobenzene anhydride ester;

the inorganic filler is one or more of calcium carbonate, calcined argil and white carbon black;

and the other auxiliary agents are an auxiliary heat stabilizer, a lubricant and the like.

The preparation method of the PVC cable material and the PVC cable comprises the following steps:

step 1: mixing the ingredients:

weighing the components according to the formula, adding PVC resin and a plasticizer into a high-speed mixer, starting stirring, waiting for the resin powder to basically absorb the plasticizer, then adding a stabilizer, adding a flame retardant, an inorganic filler and the rest of auxiliary agents when the temperature of the materials is raised to about 85 ℃, continuously stirring the materials to about 110 ℃, stopping stirring, mixing the materials, and plastifying on an open mill.

Step 2: plastication

The roller temperature of the open mill is set, the front roller temperature is 165 +/-5 ℃, the rear roller temperature is 160 +/-5 ℃, and the roller spacing of the open mill is adjusted to be small. And then adding the mixed materials into an open mill, plasticating until the surfaces of the materials are smooth and have no crack, and then discharging the sheets.

And step 3: tabletting

The temperature of the vulcanizing press is set to be 170 ℃, after the temperature is kept constant for one hour, the plasticated materials are put into a die, and are placed on the vulcanizing press to be hot-pressed for 6min under the pressure of 20MPa, and bubbles are discharged to ensure that no bubbles exist in the sheet. Then cold pressing is carried out for 5min at 30 ℃ under the same pressure, thus obtaining the PVC sheet with the length of 220mm, the width of 220mm and the thickness of 4 mm.

And 4, step 4: cable preparation

And (4) coating the cable material obtained in the step (3) on a metal wire by using an extruder according to a conventional process to obtain the cable.

The invention has the beneficial effects that: 2-amino-3- (naphthalene-2-yl) octyl propionate is used as a novel PVC environment-friendly plasticizer, and a preparation process thereof is disclosed. And further discloses an environment-friendly PVC cable material and a preparation process of the cable. The obtained environment-friendly cable avoids the use of phthalate plasticizer, but the performance of the environment-friendly cable is not obviously different from that of PVC cable taking phthalate as plasticizer.

Detailed Description

The present invention will be further described in detail with reference to the following examples, which are illustrative of the present invention and are not intended to limit the present invention in any way. Reagents, methods and apparatus used in the present invention are conventional in the art unless otherwise indicated.

Example 1: preparation of octyl 2-amino-3- (naphthalen-2-yl) propionate

2.15g of 2-amino-3- (naphthalen-2-yl) propionic acid and 6.5g of N-octanol were added to 17mL of 1, 4-dioxane, 17mL of 4N HCl/1, 4-dioxane solution was added, and the reaction mixture was stirred and allowed to stand at room temperature for 4 days to react. After the reaction, 450mL of diethyl ether was added, and the mixture was stirred at room temperature for 1.5 hours. The reaction mixture was filtered, and the precipitate was collected by filtration, washed with 50mL of diethyl ether, and dried under vacuum to obtain 3.09g of a compound having a purity of 95.8%.

The resulting compound ¹ The H-NMR data are as follows:

¹ H NMR (500 MHz, Chloroform-d) δ 7.83 (dt, J = 7.7, 2.0 Hz, 1H), 7.81 – 7.74 (m, 2H), 7.62 (t, J = 2.3 Hz, 1H), 7.55 – 7.44 (m, 2H), 7.26 (dd, J = 8.5, 2.2 Hz, 1H), 4.04 (t, J = 6.5 Hz, 2H), 3.93 (p, J = 6.8 Hz, 1H), 3.10 (dd, J = 14.4, 6.7 Hz, 1H), 3.02 (dd, J = 14.4, 6.7 Hz, 1H), 2.92 – 2.86 (m, 1H), 2.61 (t, J = 7.1 Hz, 1H), 1.71 – 1.62 (m, 2H), 1.42 – 1.23 (m, 10H), 0.94 – 0.85 (m, 3H)。

m/z:327.22

example 2: preparation of PVC cable material with octyl 2-amino-3- (naphthalene-2-yl) propionate as plasticizer

The prescription is as follows:

the preparation method comprises the following steps:

step 1: ingredient mixing

Weighing the materials according to the mass percentage in the formula, firstly adding PVC resin and a plasticizer into a high-speed mixer, heating to 60 ℃, starting stirring, waiting for the PVC to basically absorb the plasticizer, then adding a stabilizer, adding a flame retardant, an inorganic filler and a lubricant when the materials are heated to about 90 ℃, continuously stirring the materials to about 110 ℃, stopping stirring, and plastifying the materials on an open mill after the materials are mixed.

Step 2: plastication

And 3, step 3: tabletting

The temperature of the vulcanizing press is set to be 170 ℃, after the temperature is kept constant for one hour, the plasticated materials are put into a die, are placed on the vulcanizing press to be hot-pressed for 6min under the pressure of 20MPa, and are subjected to bubble discharge for a plurality of times to ensure that no bubbles exist in the sheet. Then cold pressing is carried out for 5min at 30 ℃ under the same pressure, thus obtaining the PVC sheet with the length of 220mm, the width of 220mm and the thickness of 4 mm.

And 4, step 4: cable preparation

Example 3 testing of the properties of the PVC sheet obtained in example 2 (Heat loss and Water extraction)

The two performances of the heating loss rate and the water extraction rate are tested to investigate the influence of different parts of 2-amino-3- (naphthalene-2-yl) octyl propionate as a plasticizer to replace dioctyl terephthalate (DOTP) on the heating loss rate and the water extraction rate of the PVC cable material.

3.1 Volatility test

The experiment is carried out according to the standard GB/T3830-2008 (soft polyvinyl chloride calendered film and sheet)

The test method comprises the steps of preparing a test piece by taking each sample obtained in the example 2, and preparing a test piece with the length of 60mm, the width of 40mm and the thickness of lmm, wherein each sample is not less than 3. Each test was placed in a desiccator and left for 4 hours before being removed. Weigh and record piece by piece. And (3) keeping the temperature of the mixture in a non-air-blowing oven at 100 +/-2 ℃ for 6 hours, taking out the mixture, immediately putting the mixture into a drier, cooling the mixture to room temperature, weighing the mixture, calculating the heating loss rate according to the following formula, and taking the average value of the results.

In the formula:

: sample mass (unit: g) before heating

: sample mass after heating (unit: g)

3.2 Water extraction Rate testing

The draw-out test was performed using distilled water. Samples of the PVC cable material obtained in example 2 were prepared to the same specifications (50 mm. Times.100 mm), and 3 samples were taken for each sample to be tested, to conduct the water extraction rate test. Before testing, the samples are placed in a dryer for 4h and then taken out, the mass of each sample is recorded, then each sample is respectively immersed in 200ml of distilled water (if the samples float on the water surface, nylon yarn series weights can be used for leading the samples to sink, and the samples are not mutually contacted or attached to the wall of a beaker), the beaker in which the samples are immersed is placed at a constant temperature of (50 +/-2) DEG C, the samples are taken out after 24h, the water is absorbed by dry filter paper, the samples are placed in a constant temperature oven of (50 +/-2) DEG C and are kept for 8h, then the samples are taken out and are cooled to the room temperature in the dryer. The tablets were weighed one by one. The water extraction (%):

in the formula:

: sample mass (unit: g) before extraction

M: mass of sample after extraction (unit: g)

The PVC sample data obtained are as follows:

	GB/T3830-2008 standard	Example 2 formulation 1	Example 2 formulation 2	Example 2 formulation 3	Example 2 formulation 4	Example 2 formulation 5
							Heating loss Rate (%)	<5%	3.5	0.3	0.5	0.5	0.7
Water extraction Rate (%)	<1%	0.3	0.1	0.2	0.2	0.2

As shown by the above data, the heating loss rate and the water extraction rate of the PVC cable material (example 2, formula 2-5) using octyl 2-amino-3- (naphthalene-2-yl) propionate as the plasticizer are much lower than those of the PVC cable material (example 2, formula 1) using dioctyl terephthalate as the plasticizer. Therefore, the PVC cable material taking the octyl 2-amino-3- (naphthalene-2-yl) propionate as the plasticizer has excellent performance and is environment-friendly.

Example 4 Properties of the respective prescription PVC cable materials obtained in example 2 were examined in accordance with GB/T8815-2008 (Flexible polyvinyl chloride Plastic for electric wire and Cable), HI-90 (electric Power Cable and other similar Cable sheaths of 35kV and below)

From the data in the table above, it can be seen that the PVC cable material using octyl 2-amino-3- (naphthalen-2-yl) propionate as a novel environmentally friendly plasticizer is not significantly different from the PVC cable material obtained under the same conditions using DOTP as a plasticizer in performance as the HI-90 cable sheath, and is even slightly better than the latter.

While the foregoing summary and examples describe the general principles and features of the present invention and the advantages of the present invention, it will be understood by those skilled in the art that the present invention is not limited by the above examples, which are only the most preferred embodiments of the present invention, but various changes and modifications can be made therein without departing from the spirit and scope of the present invention, wherein octyl 2-amino-3- (naphthalen-2-yl) propionate is used as the plasticizer of PVC cable material, and the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A novel PVC plasticizer 2-amino-3- (naphthalene-2-yl) octyl propionate is characterized by having the following chemical structure:

。

2. the octyl 2-amino-3- (naphthalen-2-yl) propionate of claim 1 prepared by the process of:

step 2: and (2) adding diethyl ether into the reaction mixture obtained in the step (1), filtering a precipitate, and washing to obtain a reaction final product, namely the 2-amino-3- (naphthalene-2-yl) octyl propionate.

3. A PVC cable material is characterized in that 2-amino-3- (naphthalene-2-yl) octyl propionate is used as a plasticizer.

4. The PVC cable material according to claim 3, wherein the PVC cable material further comprises heat stabilizer, flame retardant, inorganic filler, lubricant.

5. An environmentally friendly cable, characterized in that the PVC cable material of claim 3 or 4 is used as an outer sheath.