CN110923842A

CN110923842A - Preparation process of non-dyed primary polyester staple fiber

Info

Publication number: CN110923842A
Application number: CN201911168054.8A
Authority: CN
Inventors: 赵成芳
Original assignee: Hangzhou Benma Chemfibre & Spinning Co Ltd
Current assignee: Hangzhou Benma Chemfibre & Spinning Co Ltd
Priority date: 2019-11-25
Filing date: 2019-11-25
Publication date: 2020-03-27
Anticipated expiration: 2039-11-25
Also published as: CN110923842B

Abstract

The invention relates to the technical field of synthetic fiber production, and discloses a preparation process of non-dyed primary polyester staple fiber, which comprises the following steps: s1: preparing color master batches; the color master batch comprises the following raw materials in parts by weight: 70-90 parts of dimethyl terephthalate, 20-40 parts of propylene glycol, 120 parts of pigment and 130 parts of dispersant; s2: treating raw materials; s3: heating and melting; s4: spinning; s5: cooling and forming; s6: oiling; s7: winding and bundling; s8: curling and cutting off; the non-dyeing primary polyester staple fiber is prepared through the steps. The color fastness of the produced polyester fiber yarns is high.

Description

Preparation process of non-dyed primary polyester staple fiber

Technical Field

The invention relates to the technical field of synthetic fiber production, in particular to a preparation process of non-dyeing primary polyester staple fiber.

Background

The primary polyester fiber is a chemical fiber with wide application, which is obtained by adopting terephthalic acid and derivatives thereof and ethylene glycol to carry out polycondensation reaction, and the modified fiber has high breaking strength and elastic modulus, excellent heat setting, good heat resistance and light resistance, and is one of the fastest-developing varieties in synthetic fibers. The polyester fiber has regular and compact molecular arrangement and high crystallinity and orientation degree, but lacks dyeable groups, so the polyester fiber has higher dyeing difficulty, higher dyeing equipment requirement and difficult solution of the three-waste treatment problem.

At present, two main types of dyeing methods for polyester fiber textiles are available, one is that a traditional spinning process is adopted to spin polyester fiber yarns into cloth, a high-temperature, high-pressure or carrier-added dyeing method is adopted, colored sewage generated in the dyeing process is difficult to treat and high in cost, and the colored sewage does not meet the national discharge standard. The other is to use the polyester fiber to color before, and the fiber is also called as non-dyed fiber. The non-dyed fiber is a colored fiber directly spun by a stock solution coloring technology, can fundamentally solve the problems of fiber dyeing consumption and wastewater discharge, and saves a large amount of dyeing cost. The dope dyeing of the non-dyed fiber means that the polyester melt (or slice) is injected with the pigment (color master batch) after drying, melting, filtering and metering before entering the spinning manifold, and the pigment and the polyester melt are uniformly mixed by a high-efficiency static mixer and then enter the spinning manifold together for spinning. In the melt spinning process, most dyeing and finishing processes can be omitted for the non-dyed fiber, and the emission of carbon dioxide and chemical oxygen demand is greatly reduced, so that the water and chemicals can be saved.

However, in the actual production process, the carrier of the color master batch often uses plastic products, and after the plastic is melted at high temperature, the plastic and the polyester in the molten state belong to different kinds of substances, so that the performance of a spinning fiber product is directly influenced, and finally, the color fastness of the produced polyester fiber yarn is low.

Disclosure of Invention

The invention aims to provide a preparation process of non-dyeing primary polyester staple fibers, which can ensure that the produced polyester fibers have high color fastness.

The technical purpose of the invention is realized by the following technical scheme:

a preparation process of non-dyeing primary polyester staple fibers comprises the following steps:

s1: preparing color master batches; the color master batch comprises the following raw materials in parts by weight: 70-90 parts of dimethyl terephthalate, 20-40 parts of propylene glycol, 120 parts of pigment and 130 parts of dispersant;

s2: treating raw materials;

s3: heating and melting;

s4: spinning;

s5: cooling and forming;

s6: oiling;

s7: winding and bundling;

s8: curling and cutting off;

the non-dyeing primary polyester staple fiber is prepared through the steps.

By adopting the technical scheme, the dimethyl terephthalate and the propylene glycol are subjected to polycondensation reaction, so that the color master batch becomes a carrier of the color master batch. The pigment and the dispersing agent are added when the color master batch is prepared, so that the pigment can be uniformly dispersed in a carrier of the master batch, the pigment can be more uniformly dispersed in the carrier, and the pigment is prevented from settling and coagulating in the carrier; the pigment is more uniformly dispersed in the carrier, so that the coloring power of the pigment on the carrier can be improved, and the loading amount of the pigment is increased.

The carrier selects dimethyl phthalate and propylene glycol as raw materials, and the raw materials are consistent with the raw materials of the polyester fibers, so that the finally prepared color master batch has better compatibility with the raw materials of the polyester fibers in the subsequent use process, and on the other hand, the pigment loading amount is increased due to the fact that the coloring power of the pigment on the carrier is improved, so that the amount of the pigment falling off from the carrier is reduced, and the color fastness of the polyester fiber yarns produced by using the color master batch is high.

As a further improvement of the invention, the S1 color master batch is prepared from the following raw materials in parts by weight: 70-90 parts of dimethyl terephthalate, 20-40 parts of propylene glycol, 150 parts of pigment 120-130 parts of dispersant 110-80 parts of stabilizer.

As a further improvement of the invention, the stabilizer comprises the following chemical compositions in percentage by mass: 30 to 50 percent of pentaerythritol stearate, 20 to 40 percent of aluminum stearate and 10 to 30 percent of ethyl oxyethanol diethyl ammonium phosphate.

By adopting the technical scheme, the stabilizer is added in the preparation process of the color master batch, so that the pigment has more stable property in a molten state, and the property of the pigment is prevented from changing, so that the color of the pigment is changed. The pentaerythritol stearate has good internal and external lubricity, can improve the thermal stability of the pigment in the color master batch, and is non-toxic, green and healthy.

The pentaerythritol stearate can also make the pigment have stronger dispersing performance and more uniform dispersion in the carrier on the premise of improving the thermal stability of the pigment. The aluminum stearate has stronger corrosion resistance, and the finally manufactured polyester fiber has stronger corrosion resistance by adding the aluminum stearate into the color master batch, so that the service life of the polyester fiber is longer. Meanwhile, the aluminum stearate can promote pentaerythritol stearate to improve the thermal stability of the pigment in the color master batch, so that the thermal stability of the pigment is stronger, and finally, the thermal stability of the color master batch for subsequently preparing the polyester fiber is better, so that the performance of the prepared polyester fiber is stronger.

The ethyl oxyethanol diethyl ammonium phosphate belongs to lipid substances, has a phosphate group and has strong coordination capacity. The ethyl oxyethanol diethyl ammonium phosphate enters into terylene molecules in a molten state and can be matched with pigment in the color master batch, so that the adhesion capability of the pigment can be improved. Meanwhile, the ethyl oxyethanol diethyl ammonium phosphate is matched with the pigment, so that the thermal stability of the pigment can be improved.

As a further improvement of the invention, the dispersing agent comprises polyethylene wax and polyethyl methacrylate, and the mass ratio of the polyethylene wax to the polyethyl methacrylate is 3: 2.

As a further improvement of the invention, the dispersing agent comprises 40-70% of polyethylene wax, 20-50% of polyethyl methacrylate and 10-40% of cetearyl ethyl hexanoate by mass percent.

Through adopting above-mentioned technical scheme, polyethylene wax has very excellent external lubrication and inside lubrication action, at the in-process of preparation masterbatch, can regard as the carrier of pigment, and simultaneously, polyethylene wax is good with dacron fibrous raw materials intermiscibility to make pigment can even dispersion on the carrier, can prevent that pigment from taking place to subside under the molten condition. The blending of the polyethyl methacrylate and the polyethylene wax can further enhance the lubricating effect of the polyethylene wax, so that the intermiscibility of the polyethylene wax and the terylene material is stronger. The cetearyl ethyl hexanoate and the polyethyl methacrylate are lipid substances and can be mixed with each other, and the cetearyl ethyl hexanoate can enable the pigment to be rapidly and uniformly dispersed in the polyethylene wax.

Because the cetearyl alcohol ethyl caproate is added into the dispersing agent, and the ethyl oxyethanol diethyl ammonium phosphate is added into the stabilizing agent, the cetearyl alcohol ethyl caproate and the ethyl oxyethanol diethyl ammonium phosphate are miscible, the color fastness of the color master batch in the subsequent use process can be stronger, and the pigment has stronger stability in the polyester fiber yarn and is not easy to change color.

As a further improvement of the invention, the fiber is oiled by S6, the fiber processed by S5 is conveyed into an oiling agent tank containing oiling agent, and the fiber is soaked for 70-100min, wherein the oiling agent comprises 27-38 parts by weight of octadecylamine polyoxyethylene ether, 23-41 parts by weight of lauryl alcohol and 47-55 parts by weight of aminopropanol kojic acid phosphate.

Because the polyester fiber is an organic polymer material, chemical bonds in macromolecules are covalent bonds, the polyester fiber can not be ionized, can not transfer electrons or ions, has high surface resistance and bulk resistance, and can generate high static electricity when the polyester fiber rubs or contacts molecules. Through carrying the cellosilk in the finish to continuously soak, thereby make to adhere to on the cellosilk and have the finish, lauryl alcohol and octadecylamine polyoxyethylene ether combine mutually, thereby make the surface of cellosilk more smooth, reduced coefficient of friction, thereby make the fabric that the cellosilk was made play the ability of static lower, finally reach antistatic effect.

As a further improvement of the invention, the oil agent comprises 30-35 parts of octadecylamine polyoxyethylene ether, 27-38 parts of lauryl alcohol, 49-54 parts of aminopropanol kojic acid phosphate, 7-15 parts of decyl betaine and 25-45 parts of hydrophilic silicone oil in parts by weight.

By adopting the technical scheme, because the decyl betaine has isoelectric points, after the decyl betaine permeates into the fiber molecules, the pH value of the fiber surface can be controlled, so that the characteristics of anions or cations can be displayed, and an oriented adsorption layer can be formed on the fiber surface, so that the conductivity of the fiber surface is effectively improved. Meanwhile, as the hydrophilic silicone oil is added into the oil agent, the decyl betaine and the hydrophilic silicone oil can act together on the fiber, so that the fiber has stronger softness, and the comfort of the fiber to the skin is finally improved.

As a further improvement of the invention, the spinning is carried out by S4, the substance treated by S3 is filtered, and the filtered substance is conveyed to a metering pump for distribution; delivering the material in the molten state distributed from the metering pump to a spinneret plate for spinning, wherein the temperature of the spinneret plate is 270-300 ℃.

Through the filtering step, impurities in the material in the molten state are less, and the quality of the polyester staple fibers prepared subsequently is better. The material in the molten state is conveyed to the spinneret plate, so that the material in the molten state can conveniently pass through the spinneret plate, and subsequent processing is facilitated.

In conclusion, the invention has the advantages and beneficial effects that:

1. the carrier selects dimethyl phthalate and propylene glycol as raw materials, and the raw materials are consistent with the raw materials of the polyester fiber, so that the finally prepared color master batch has better compatibility with the raw materials of the polyester fiber in the subsequent use process, and on the other hand, the pigment has improved tinting strength on the carrier and increased loading amount, so that the amount of the pigment falling off from the carrier is reduced, and the color fastness of the polyester fiber yarn produced by using the color master batch is high;

2. the pentaerythritol stearate has good internal and external lubricity, can improve the thermal stability of the pigment in the color master batch, and is non-toxic, green and healthy. The pentaerythritol stearate can also make the pigment have stronger dispersing performance and more uniform dispersion in the carrier on the premise of improving the thermal stability of the pigment;

3. the cetearyl ethyl hexanoate and the polyethyl methacrylate are lipid substances and can be mixed with each other, and the cetearyl ethyl hexanoate can enable the pigment to be rapidly and uniformly dispersed in the polyethylene wax;

4. the cetearyl alcohol ethyl hexanoate and the ethyl oxyethanol diethyl ammonium phosphate are miscible, so that the color fastness of the color master batch in the subsequent use process is stronger, and the pigment has stronger stability in the polyester fiber yarns and is difficult to change color.

Drawings

FIG. 1 is a process flow chart of a preparation process of the non-dyed primary polyester staple fiber of the invention.

Detailed Description

The present invention will be described in further detail with reference to the accompanying drawings and examples.

Example 1:

referring to fig. 1, a preparation process of a non-dyed primary polyester staple fiber comprises the following steps:

s1: and (4) preparing color master batches. The color master batch comprises the raw materials of, by weight, 80 parts of dimethyl terephthalate, 30 parts of propylene glycol, 135 parts of pigment, 120 parts of dispersant and 60 parts of stabilizer; wherein the dispersing agent comprises 55% of polyethylene wax, 35% of polyethyl methacrylate and 10% of cetearyl ethyl hexanoate by mass percent; wherein the chemical compositions of the stabilizer comprise 40 percent of pentaerythritol stearate, 30 percent of aluminum stearate and 30 percent of ethyl oxyethanol diethyl ammonium phosphate by mass percentage.

Putting the raw materials of the color master batch into a slurry kettle in a non-sequential manner, and putting a catalyst into the slurry kettle, wherein the catalyst is a mixture of zinc acetate and antimony trioxide; meanwhile, the slurry kettle is vacuumized, and the vacuum degree is adjusted to 70 Pa. The mass ratio of the added mass of the catalyst to the masterbatch raw material is 1: 100. The temperature in the slurry kettle was then adjusted so that the temperature in the slurry kettle increased to 170 ℃, and stirring was started, continued for the esterification reaction, for a duration of 2.5 h. And then conveying the materials in the slurry kettle to a polycondensation kettle, adjusting the temperature in the polycondensation kettle to 280 ℃, adjusting the vacuum degree of the polycondensation kettle to 70Pa, and continuously keeping the temperature for 4 hours to prepare the color master batch. The pigment is selected from one of phthalocyanine blue, phthalocyanine green, macromolecular red and carbon black.

S2: and (4) processing raw materials. Drying ethylene glycol, terephthalic acid and titanium glycol to control the moisture content of the titanium glycol to be less than 0.01 percent. The raw materials comprise the following components in parts by weight: 500 parts of ethylene glycol, 500 parts of terephthalic acid and 5 parts of ethylene glycol titanium.

S3: heating and melting. The color master batch treated by the S1 and the ethylene glycol treated by the S2 are added into a reaction kettle, the temperature of the reaction kettle is increased to 60 ℃, and the mixture is stirred for 1.5 hours. Then adding terephthalic acid and ethylene glycol titanium into the reaction kettle in the step, raising the temperature in the reaction kettle to 280 ℃, and continuously reacting for 4 hours, wherein the vacuum degree in the reaction kettle is controlled at 70 Pa. The mass ratio of the color master batch prepared by the S1 to the material processed by the S2 raw material is 2: 5.

After the reaction is finished, the materials in the reaction kettle are conveyed into a screw extruder, the temperature in the screw extruder is adjusted to 310 ℃, and the temperature is kept for 50 min. The contents of the screw extruder were then fed to a metering pump.

S4: and (6) spinning. The material after the metering pump is conveyed to the spinneret plate, and the material is continuously flushed towards the spinneret plate, so that the polyester fiber is continuously flushed from one side to the other side of the spinneret plate, and the polyester fiber is changed into the polyester fiber. The polyester fiber is delivered to any temperature between 270 ℃ and 300 ℃ at the spinneret and coated with atomized silicone oil.

S5: and (5) cooling and forming. The fiber filaments sprayed from the spinneret were blown using an air conditioner with the air temperature kept at 25 ℃.

S6: and (6) oiling. And conveying the material treated by the S5 into an oil agent groove containing an oil agent, and soaking for 85min, wherein the oil agent comprises 33 parts by weight of octadecylamine polyoxyethylene ether, 32 parts by weight of lauryl alcohol, 51 parts by weight of aminopropanol kojic acid phosphate, 11 parts by weight of decyl betaine and 35 parts by weight of hydrophilic silicone oil.

S7: and (5) winding and bundling. And winding and bundling the primary fiber after the S6 treatment.

S8: and (5) cutting the coil. And conveying the material processed by the S7 to a crimping machine for crimping, and cutting the material after crimping into cut wires.

After the steps, the non-dyeing primary polyester staple fiber with high color fastness is prepared.

Examples 2-5 differ from example 1 in that the raw materials for the color masterbatch in step S1 color masterbatch preparation are shown in table 1 in parts by weight: unit: portions are

TABLE 1

	Example 2	Example 3	Example 4	Example 5
					Pigment (I)	120	150	130	140
Terephthalic acid dimethyl ester	70	90	75	85
					Dispersing agent	110	130	115	125
Propylene glycol	20	40	25	35
					Stabilizer	40	80	50	70

Examples 6-10 differ from example 1 in that the chemical compositions of the stabilizer in the step S1 color masterbatch preparation are shown in table 2 in mass percent: unit: is based on

TABLE 2

	Example 6	Example 7	Example 8	Example 9	Example 10
						Pentaerythritol stearate	30	50	50	35	50
Aluminum stearate	40	20	40	35	25
						Ethoxyethanol diethyl ammonium phosphate ester	30	30	10	30	25

Examples 11-15 differ from example 1 in that the respective chemical compositions of the dispersant in the step S1 color masterbatch preparation are shown in table 3 in mass percent: unit: is based on

TABLE 3

	Example 11	Example 12	Example 13	Example 14	Example 15
						Polyethylene wax	40	70	50	40	45
Polymethylacrylate	50	20	30	20	25
						Cetearyl ethyl hexanoate	10	10	20	40	30

Examples 16 to 19 differ from example 1 in that the respective chemical compositions of the oil in the oil applied in step S6 are shown in table 4 in parts by weight: unit: portions are

TABLE 4

	Example 16	Example 17	Example 18	Example 19
					Octadecamine polyoxyethylene ether	30	35	32	34
Lauryl alcohol	27	38	30	35
					Aminopropanol kojic acid phosphate ester	49	54	50	52
Decyl betaine	7	15	9	13
					Hydrophilic silicone oil	25	45	30	40

Example 20 differs from example 1 in that the S1 masterbatch was prepared without a stabilizer in the masterbatch raw material.

Example 21 is different from example 1 in that in the step of preparing the S1 color masterbatch, the dispersing agent in the raw materials of the color masterbatch includes polyethylene wax and polyethyl methacrylate, and the mass ratio of the polyethylene wax to the polyethyl methacrylate is 3: 2.

Example 22 differs from example 1 in that in the oiling step in S6, the chemical compositions of the oil agent are, in parts by weight, 33 parts of octadecylamine polyoxyethylene ether, 32 parts of lauryl alcohol and 51 parts of aminopropanol kojic acid phosphate.

Comparative example 1: the difference from the example 1 is that in the step of preparing the S1 color master batch, no dispersant is added to the raw materials of the color master batch.

Comparative example 2: the difference from example 1 is that the oil used in the oiling in step S6 is the oil described in the specification with application publication No. CN 105586683A.

Test one: and (5) measuring color fastness.

The non-dyed virgin polyester staple fibers prepared in examples 1, 20, 21, 22 and 1-2 were woven into polyester fabrics, each numbered A, B, C, D, E, F, and six polyester fabrics were tested for crockfastness according to GB/T3920-1997 and a crockfastness tester, and the data are shown in Table 5.

TABLE 5

And (3) data analysis:

as can be directly seen from table 5, the color fastness of the terylene fabric corresponding to the number a is the highest, and the color fastness of the terylene fabric corresponding to the number B is finally reduced because the raw material of the color master batch only contains cetearyl ethyl hexanoate and does not combine with ethyl oxyethanol diethyl ammonium phosphate because no stabilizer exists in the number B. Similarly, the reason for the code C is that the dispersing agent in the example 21 does not contain cetearyl ethyl hexanoate, and can not be combined with ethyl oxyethanol diethyl ammonium phosphate, so that the color fastness of the polyester fabric is reduced; meanwhile, the color fastness of the color master batch of the number C is lower than that of the number B because the color master batch of the number B does not contain the cetearyl ethyl hexanoate, and the cetearyl ethyl hexanoate and the polyethyl methacrylate can accelerate the dispersion speed of the pigment in the polyethylene wax, so that the color fastness of the polyester fabric of the number B is higher than that of the polyester fabric of the number C. Since comparative example 1 does not contain a dispersant, the pigment dispersion effect is poor, and the color fastness of the polyester fabric corresponding to number E is finally the lowest.

And (2) test II: and measuring the K/S value.

The non-dyed virgin polyester staple fibers prepared in examples 1, 20, 21, 22 and 1 to 2 were woven into polyester fabrics, each numbered A, B, C, D, E, F, and then color-measured using a Datacolor SF600X computer color measuring and matching machine at λ_maxThe K/S values of six polyester fabrics were measured 10 times for each sample, averaged, and the average value was recorded in Table 6.

And (3) test III: and (4) measuring the antistatic performance.

The non-dyed virgin polyester staple fibers prepared in examples 1, 20, 21, 22 and 1 to 2 were woven into terylene fabrics, each numbered A, B, C, D, E, F, and then six terylene fabrics were tested by the fabric antistatic test method of AATCC 76-1995: the antistatic ohmic test is carried out on the test material at the preparation distance of the antistatic meter and the electrode pair, and the larger the antistatic ohmic value R is, the poorer the antistatic capability is; the antistatic ohmic value R is also recorded in table 6.

And (4) testing: and (6) testing flexibility.

The non-dyed virgin polyester staple fibers prepared in examples 1, 20, 21, 22 and 1 to 2 were woven into polyester fabrics, each numbered A, B, C, D, E, F, and then six regenerated polyester fabrics were touched by 100 persons at random, and the softness of six regenerated polyester fabrics was recorded. The softness value is divided into 1-10 grades from low to high, and the grade 10 has the highest softness, namely the best softness. Then 6 persons were randomly selected from the 100 persons, the softness after the 6 persons had touched was averaged, and the average of their softness was recorded, and then the average of softness was recorded in table 6.

TABLE 6

Numbering	K/S value	R/Ω	Softness
				A	24.7	835	8
B	12.3	838	7
				C	18.8	841	7
D	24.3	973	4
				E	19.2	839	7
F	24.5	1124	3

And (3) data analysis:

in Table 6, it is apparent from comparison of the data in the column of K/S values that the maximum K/S value of the number A, the maximum K/S value of the polyester fabric described in example 1 and the darkest color-dyeing are obtained, and thus the pigment properties are most stable in the production method of example 1. The lowest K/S value, the lowest K/S value and the lightest color-dyeing using the Dacron fabric of example 20 were used, indicating that the pigment stability was the worst in the preparation method of example 1. The most deterioration of the pigment occurs.

In table 6, it can be seen from a list of data of the antistatic ohmic value R that R of the number a is the smallest, the antistatic ohmic value of the regenerated polyester fabric produced using the regenerated polyester staple fiber described in example 1 is the smallest, and R of the number F is the largest, and the antistatic ohmic value of the regenerated polyester fabric produced using the regenerated polyester staple fiber described in comparative example 2 is the largest.

In table 6, it can be seen from a list of data on softness that the softness of the polyamide fabric of item a is the highest, the softness of the polyamide fabric produced by the method described in example 1 is better, and the softness of the polyamide fabric of item F is the lowest, and the softness of the polyamide fabric produced by the method described in comparative example 2 is the lowest. Thus, the use of the finish described in example 1 can improve the flexibility of the polyester staple fibers.

The above description is only a preferred embodiment of the present invention, and the protection scope of the present invention is not limited to the above embodiments, and all technical solutions belonging to the idea of the present invention belong to the protection scope of the present invention. It should be noted that modifications and embellishments within the scope of the invention may occur to those skilled in the art without departing from the principle of the invention, and are considered to be within the scope of the invention.

Claims

1. A preparation process of non-dyeing primary polyester staple fiber is characterized by comprising the following steps: the method comprises the following steps:

s2: treating raw materials;

s3: heating and melting;

s4: spinning;

s5: cooling and forming;

s6: oiling;

s7: winding and bundling;

s8: curling and cutting off;

the non-dyeing primary polyester staple fiber is prepared through the steps.

2. The process for preparing non-dyeing primary polyester staple fiber according to claim 1, characterized in that: the S1 color master batch is prepared from the following raw materials in parts by weight: 70-90 parts of dimethyl terephthalate, 20-40 parts of propylene glycol, 150 parts of pigment 120-130 parts of dispersant 110-80 parts of stabilizer.

3. The process for preparing non-dyeing primary polyester staple fiber according to claim 2, characterized in that: the stabilizer comprises the following chemical components in percentage by mass: 30 to 50 percent of pentaerythritol stearate, 20 to 40 percent of aluminum stearate and 10 to 30 percent of ethyl oxyethanol diethyl ammonium phosphate.

4. The process for preparing non-dyeing primary polyester staple fiber according to claim 1, characterized in that: the dispersing agent comprises polyethylene wax and polyethylmethacrylate, and the mass ratio of the polyethylene wax to the polyethylmethacrylate is 3: 2.

5. The process for preparing non-dyeing primary polyester staple fiber according to claim 3, characterized in that: the dispersing agent comprises, by mass, 40% -70% of polyethylene wax, 20% -50% of polyethyl methacrylate and 10% -40% of cetearyl ethyl hexanoate.

6. The process for preparing non-dyeing primary polyester staple fiber according to claim 1, characterized in that: and oiling in the S6, and conveying the fiber yarn treated in the S5 mode into an oiling agent tank containing an oiling agent to be soaked for 70-100min, wherein the oiling agent comprises 27-38 parts by weight of octadecylamine polyoxyethylene ether, 23-41 parts by weight of lauryl alcohol and 47-55 parts by weight of aminopropanol kojic acid phosphate.

7. The process for preparing non-dyeing primary polyester staple fiber according to claim 6, wherein the process comprises the following steps: the oil agent comprises, by weight, 30-35 parts of octadecylamine polyoxyethylene ether, 27-38 parts of lauryl alcohol, 49-54 parts of aminopropanol kojic acid phosphate, 7-15 parts of decyl betaine and 25-45 parts of hydrophilic silicone oil.

8. The process for preparing non-dyeing primary polyester staple fiber according to claim 1, characterized in that: the S4 spinning, filtering the substance treated by the S3, and conveying the filtered substance to a metering pump for distribution; delivering the material in the molten state distributed from the metering pump to a spinneret plate for spinning, wherein the temperature of the spinneret plate is 270-300 ℃.