Preparation and low-temperature sizing process of easily degradable corn native starch size

Abstract

The invention discloses a preparation and low-temperature sizing process of easily degradable corn native starch slurry. The preparation method comprises the following steps: adding 37.5-112.5 kg of native starch, 0-80 g of a viscosity reducer and 950-1000 L of water into a high-pressure size mixing barrel, heating to 116-120 DEG C, controlling the pressure to be 0.18-0.22 MPa, covering the size for 25-35 minutes, inputting into a normal-pressure size mixing barrel, and mixing with 20-40 parts of glycerol, 6-8 parts of palm oil, 1-5 parts of wax slices, 2-3 parts of sodium alginate, 3-4 parts of carboxymethyl beta-cyclodextrin, 20-40 parts of fatty alcohol-polyoxyethylene ether and 5-15 parts of an organic silicon compound. In the yarn sizing process, the temperature of a size tank is controlled to be 75-85 DEG C, and the sizing speed is controlled to be 80-90 m / min. The size viscosity is 19-21 mPa.s, the sizing percentage is 3-8%, the sizing moisture regain is 10-15%, and the pressure of a sizing machine is 30-50 KN. The BOD5 / COD of desizing wastewater of the sizing agent is larger than 0.60, the biodegradability is high, the congelation resistance of the sizing agent is high, and the sizing agent has the advantage of low-temperature sizing.

Description

Technical Field

[0001] The invention relates to the field of textile warp yarn sizing, and in particular to the preparation of easily degradable corn native starch sizing material and a low-temperature sizing process. Background Art

[0002] Warp yarn sizing is a key process in textile production. Through the sizing process, the sizing agent is wrapped on the outer layer of the warp yarn, which can flatten the surface hairiness of the yarn, give the warp yarn a certain strength and wear resistance, and improve weaving efficiency.

[0003] Polyvinyl alcohol (PVA), polyacrylic acid (PAA), and starch slurry are the three most widely used slurries. PVA is a chemical slurry with excellent film strength, wear resistance, and high adhesion strength to yarn, which solves many problems in sizing. However, PVA slurry has a great impact on the environment. The chemical oxygen demand of desizing wastewater is high (COD is 4000-8000 mg / L), the biodegradability is poor (BOD5 / COD<0.10), and desizing produces a large amount of difficult-to-degrade wastewater, which has caused a great burden on the ecological environment. PAA slurry has excellent adhesion to synthetic fibers, but it has the disadvantage of moisture absorption and re-adhesion. Although it pollutes the environment less than PVA (BOD5 / COD<0.40), it is more expensive and is generally only used as an auxiliary slurry. Starch has a long history of application in sizing. It has good sizing properties, abundant resources, low price, and will not pollute the environment. It is a renewable and environmentally friendly slurry.

[0004] There are some significant problems with existing starch slurries, including: easy freezing under low temperature conditions and poor viscosity stability, so sizing is usually required under high temperature conditions (90-95°C), resulting in high energy consumption; a higher sizing rate is often used in the sizing process, and the slurry has low permeability to the warp yarn, so the slurry coverage rate on the warp yarn surface is very high, forming a thick but brittle slurry film, which reduces yarn quality and weaving efficiency; during desizing, due to the addition of PVA, PAA or other complex synthetic chemicals that are difficult to degrade, the desizing wastewater contains a large amount of organic pollutants and a high BOD5 / COD, which has irreversible effects on the environment.

[0005] Therefore, the present invention adopts the physicochemical treatment technology enhanced by auxiliary agents, develops an easily degradable corn starch environment-friendly starch slurry, optimizes its sizing process under low temperature conditions, obtains sizing yarn with excellent quality, and improves weaving production efficiency. Summary of the invention

[0006] In view of the problems existing in the above-mentioned prior art, the technical problem to be solved by the present invention is to provide a preparation method of easily degradable corn starch slurry and a low-temperature sizing process.

[0007] In a first aspect, the present invention provides a preparation method of easily degradable corn starch slurry and a low-temperature sizing process, the process comprising the following steps:

[0008] Step 1, adding corn starch, viscosity reducer and water into a high-pressure slurry mixing device;

[0009] Cover the high-pressure mixing barrel, turn on the agitator to 950-970r / min, and simmer the slurry for a certain period of time at the set temperature and pressure; after the simmering is completed, enter the normal pressure mixing barrel;

[0010] Step 2, adding a sizing accelerator to a normal pressure slurry mixing device, adjusting the stirrer to 170-190 r / min, and stirring to obtain the target starch slurry;

[0011] Step 3: Input starch slurry into the sizing machine. During the yarn sizing process, control the sizing tank temperature to 75-85°C and the sizing machine speed to 80-90 m / min. After the sizing is completed, the finished yarn is obtained.

[0012] A second aspect of the present invention provides a finished yarn product, which is obtained by using the above-mentioned sizing process.

[0013] Beneficial effects of the present invention:

[0014] 1. The slurry has strong anti-freezing property and the sizing process consumes less energy. By simplifying the slurry formula, the slurry mixing process time is shortened. In terms of slurry performance, the slurry has low viscosity, high stability, and strong anti-coagulation property, which is easy to use, store and transport.

[0015] 2. The sizing quality is excellent and the weaving efficiency is significantly improved, including reducing the amount of sizing material, improving the yarn breaking strength and wear resistance, and reducing the hairiness index.

[0016] 3. Desizing wastewater is easy to degrade, and has significant energy-saving and emission-reduction effects. Since most of the raw materials used in the sizing compounding process are natural extracts, the subsequent treatment of desizing wastewater can be completed through a simple enzyme desizing process. The desizing wastewater BOD5 / COD>0.60, the difficulty of wastewater treatment is reduced, and the environmental protection effect is significant. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is a product picture of starch slurry;

[0018] Figure 2 The schematic diagram of the starch slurry sizing the warp yarn;

[0019] Figure 3 Cross-section images of vortex-spun yarns were taken for laser confocal microscopy. DETAILED DESCRIPTION

[0020] The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments.

[0021] The present invention comprises the following steps:

[0022] (1) Add 37.5-112.5kg corn starch, 0-80g viscosity reducer and 950-1000L water to the high-pressure pulp mixing equipment. Cover the high-pressure pulp mixing barrel, turn on the agitator to high speed 950-970r / min, raise the temperature to 116-120℃, the pressure is 0.18-0.22MPa, and slurry for 25-35min. After the slurry is slurried in the high-pressure pulp mixing equipment, it is input into the normal pressure pulp mixing barrel.

[0023] The present application uses a viscosity reducer to adjust the viscosity of the starch slurry so that the slurry can maintain appropriate fluidity after gelatinization;

[0024] Furthermore, 950-970r / min can provide sufficient shear force to fully dissolve starch granules in water, but will not destroy the structure of starch due to excessive shear force, resulting in a decrease in viscosity.

[0025] Furthermore, 116-120°C is above the gelatinization temperature range of starch, which can ensure that the starch granules completely absorb water and swell to form a stable colloidal structure.

[0026] Furthermore, 0.18-0.22 MPa can ensure that the slurry is more evenly distributed in the container during the slurry mixing process, avoiding problems such as local overheating or uneven cooling.

[0027] Furthermore, the viscosity reducing agent is one or more of amylase, persulfate, hydrogen peroxide and hypochlorite.

[0028] (2) Add 20-40 parts of glycerol, 6-8 parts of palm oil, 1-5 parts of wax flakes, 2-3 parts of sodium alginate, 3-4 parts of carboxymethyl β-cyclodextrin, 20-40 parts of fatty alcohol polyoxyethylene ether, and 5-15 parts of organic silicon compound in order in a normal pressure slurry mixing device as a sizing accelerator. Adjust the stirrer to a low speed of 170-190 r / min, stir for 10 minutes, and the target starch slurry is obtained.

[0029] The addition of glycerol in the present application can form hydrogen bonds between starch molecular chains, reduce the cohesive force of the slurry, help improve the fluidity of the slurry, and can adjust the concentration of the starch slurry, increase the flexibility of the starch slurry, and make it easier to combine with the yarn.

[0030] The addition of sodium alginate and carboxymethyl β-cyclodextrin in the present application can dynamically adjust the viscosity and fluidity of the slurry, reduce the solidification point of the slurry, and improve its stability at low temperatures.

[0031] The palm oil and wax flakes added in the present application can be used as lubricants in the slurry, and can be evenly covered on the surface of the yarn to form a layer of protective medium, which can further protect the yarn and reduce wear and tear and breakage.

[0032] The present application introduces a nonionic surfactant, fatty alcohol polyoxyethylene ether, which can reduce the surface tension of the size on the warp yarn and increase the coating and uniformity of the starch size.

[0033] The addition of the organosilicon compound in the present application can form a film between water and starch, thereby improving the dispersibility of starch molecules.

[0034] The addition of glycerol in the present application also has an antifreeze effect, which prevents the starch slurry from freezing at low temperatures by lowering the freezing point and slowing down the movement of water molecules.

[0035] Furthermore, during the stirring process at 170-190 r / min for 10 min, the sizing accelerator can fully contact with the gelatinized starch.

[0036] (3) Input starch slurry to the sizing machine. During the yarn sizing process, the sizing tank temperature is controlled to be 75-85°C, the slurry viscosity is controlled to be 19-21 mPa·s, the sizing machine speed is controlled to be 80-90 m / min, the sizing rate is controlled to be 3-8%, the sizing regain is controlled to be 10-15%, and the sizing machine pressure is controlled to be 30-50 KN. After the sizing is completed, the finished yarn is obtained.

[0037] The sizing tank temperature in the sizing process of the present application is 75-85°C, which is the low-temperature sizing temperature range of the present process, and can avoid energy loss caused by high temperature. At this temperature, the viscosity of the slurry is maintained at 19-21 mPa·s.

[0038] When the sizing machine speed is 80-90m / min, the sizing agent has enough time to penetrate into the fiber gaps of the yarn, ensuring that the sizing agent can be evenly distributed on the yarn, thereby improving the quality and strength of the yarn. If the speed is too fast, the sizing agent will not have enough time to penetrate, which may lead to uneven sizing and increase the number of interrupted warps in the subsequent weaving process. If the speed is too slow, although it can increase the penetration time, it may cause the sizing agent to penetrate too much, making the yarn too stiff and increasing the difficulty of weaving.

[0039] The present application controls the sizing rate to be 3-8%, the moisture regain of the sizing yarn to be 10-15%, and the pressure of the sizing machine to be 30-50KN, based on the principle of "high moisture regain, high pressure sizing force, and low sizing rate" of the present process.

[0040] Further, the yarn raw material is cotton or polyester-cotton; the obtained sizing yarn has a sizing coverage of 20-25% and a penetration of 40-45%. Figure 1 .

[0041] Example 1 Low-temperature sizing process for vortex spinning yarn

[0042] Add 37.5kg corn starch and 950L water to the high-pressure pulping equipment. Cover the high-pressure pulping barrel tightly, turn on the agitator to high speed, raise the temperature to 116℃, the pressure to 0.18MPa, and slurry for 25 minutes. After the slurry is slurried in the high-pressure pulping equipment, it is input into the normal pressure pulping barrel.

[0043] In the normal pressure slurry mixing equipment, 20 parts of glycerol, 6 parts of palm oil, 1 part of wax flakes, 2 parts of sodium alginate, 3 parts of carboxymethyl β-cyclodextrin, 20 parts of fatty alcohol polyoxyethylene ether, and 5 parts of organic silicon compound were added in sequence as sizing accelerators. After stirring at low speed for 10 minutes, corn starch slurry was obtained. The product of starch slurry is shown in the figure below. Figure 2 As shown, it is a white viscous fluid.

[0044] The starch slurry was input into the sizing machine. During the sizing process of the vortex spinning line, the slurry tank temperature was controlled to be 75°C, the slurry viscosity was 19mPa·s, the sizing machine speed was 80m / min, the sizing rate was 3%, the sizing regain was 10%, and the sizing machine pressure was 30KN.

[0045] The cross section of the vortex-spun yarn was photographed by laser confocal microscopy. Figure 3 As shown, it is found that the outer circle of the sizing yarn cross-section has less dark black part, while the internal fiber gaps are filled with more, which indicates that the coverage rate of the process of this embodiment is low and the permeability is high.

[0046] Example 2 Low temperature sizing process for air-spun yarn

[0047] Add 40kg corn starch and 1000L water to the high-pressure pulping equipment. Cover the high-pressure pulping barrel tightly, turn on the agitator to high speed, raise the temperature to 118℃, the pressure to 0.2MPa, and slurry for 30 minutes. After the slurry is slurried in the high-pressure pulping equipment, it is input into the normal pressure pulping barrel.

[0048] 40 parts of glycerol, 6 parts of palm oil, 3 parts of wax flakes, 2 parts of sodium alginate, 3 parts of carboxymethyl β-cyclodextrin, 40 parts of fatty alcohol polyoxyethylene ether, and 8 parts of organic silicon compound were added in order in the normal pressure slurry mixing equipment as sizing accelerators. After stirring at low speed for 10 minutes, corn starch slurry was obtained.

[0049] The starch slurry was input into the sizing machine. During the sizing process on the air-spinning line, the slurry tank temperature was controlled to be 80°C, the slurry viscosity was 19mPa·s, the sizing machine speed was 85m / min, the sizing rate was 8%, the sizing regain was 12%, and the sizing machine pressure was 35KN.

[0050] Example 3 Low temperature sizing process for compact spinning yarn

[0051] Add 50kg corn starch and 1000L water to the high-pressure pulping equipment. Cover the high-pressure pulping barrel tightly, turn on the agitator to high speed, raise the temperature to 118℃, the pressure to 0.2MPa, and slurry for 30 minutes. After the slurry is slurried in the high-pressure pulping equipment, it is input into the normal pressure pulping barrel.

[0052] 30 parts of glycerol, 7 parts of palm oil, 4 parts of wax flakes, 3 parts of sodium alginate, 4 parts of carboxymethyl β-cyclodextrin, 30 parts of fatty alcohol polyoxyethylene ether, and 10 parts of organic silicon compound were added in order in the normal pressure slurry mixing equipment as sizing accelerators. After stirring at low speed for 10 minutes, corn starch slurry was obtained.

[0053] The starch slurry was input into the sizing machine. During the sizing process of the compact spinning yarn, the slurry tank temperature was controlled to be 80°C, the slurry viscosity was 21mPa·s, the sizing machine speed was 86m / min, the sizing rate was 6%, the sizing regain was 13%, and the sizing machine pressure was 40KN.

[0054] Example 4 Low temperature sizing process for ring spinning yarn

[0055] Add 112.5kg corn starch, 80g ammonium persulfate and 1000L water into the high-pressure pulping equipment. Cover the high-pressure pulping barrel tightly, turn on the agitator to high speed, raise the temperature to 120℃, the pressure to 0.22MPa, and slurry for 35 minutes. After the slurry is slurried in the high-pressure pulping equipment, it is input into the normal pressure pulping barrel.

[0056] 40 parts of glycerol, 8 parts of palm oil, 5 parts of wax flakes, 3 parts of sodium alginate, 4 parts of carboxymethyl β-cyclodextrin, 40 parts of fatty alcohol polyoxyethylene ether, and 15 parts of organic silicon compound were added in order in the normal pressure slurry mixing equipment as sizing accelerators. After stirring at low speed for 10 minutes, the corn starch slurry was obtained.

[0057] The starch slurry was input into the sizing machine. During the sizing process of the ring spinning line, the slurry tank temperature was controlled to be 85°C, the slurry viscosity was 21mPa·s, the sizing machine speed was 90m / min, the sizing rate was 8%, the sizing regain was 15%, and the sizing machine pressure was 50KN.

[0058] The yarn raw material in the above embodiment is C40 pure cotton yarn with a yarn fineness of 14.58 tex, and the finished product is tested and its indicators are evaluated:

[0059] In terms of sizing quality: compared with other processes, the sizing rate of starch sizing in this process is 12.3%, which is lower than that of polyvinyl alcohol sizing (16.52%) and polyacrylic acid sizing (16.86%), reducing the amount of sizing. The sizing rate calculation formula is (G1-G 2) / G2, G1 and G2 are the dry weights of yarn before and after sizing, respectively.

[0060] Yarn breaking strength: The breaking strength of the yarn after sizing is increased to 322.7cN, which is higher than that of polyvinyl alcohol sizing (254.6cN) and polyacrylic acid sizing (240.4cN). The elongation at break is 4.87%, which is higher than that of polyvinyl alcohol sizing (4.73%) and polyacrylic acid sizing (4.7%). The breaking strength and elongation at break of sizing yarn are tested using HD021N+ electronic strength meter according to standard GB / T3961-1997, with a sample length of 500mm and a tensile speed of 500mm / min.

[0061] Abrasion resistance times: The abrasion resistance times are increased to 39 times, which is higher than that of polyvinyl alcohol slurry (25 times) and polyacrylic acid slurry (27 times). The Y731 type cohesion tester is used to test the abrasion times of the yarn according to the standard FZ / T01058-1999, and 20 groups of test samples are used.

[0062] Hairiness index: The hairiness reduction rate is 72.82%, which is lower than that of polyvinyl alcohol slurry (75.54%) and polyacrylic acid slurry (73.13%). The hairiness reduction rate is calculated as (Y1-Y 2) / Y1, Y1 is the average index of hairiness of 3mm and above on 10cm long original yarn; Y2 is the average index of hairiness of 3mm and above on 10cm long sized yarn. The hairiness index is tested by using a hairiness yarn tester according to standard FZ / T01058-1999, and 20 sets of data are tested for each yarn.

[0063] In general, all indicators have been significantly improved. The low-temperature sizing process and the lower sizing rate reduce the sizing cost. Due to the principle of "high moisture regain, high pressure sizing force, and low sizing rate" in the sizing process, the warp breakage rate is low during the weaving process, and the weaving efficiency can be increased from 83% to about 93%.

[0064] In addition, compared with traditional chemical slurries such as polyvinyl alcohol and polyacrylic acid slurries, the starch slurry used in this process is more environmentally friendly and will not produce highly sticky dust during the weaving process, thereby effectively avoiding the problems of sticking and clogging of the filter membrane in the workshop air-conditioning system and greatly reducing maintenance costs.

[0065] In summary, the present invention discloses a preparation method of easily degradable corn starch slurry and a low-temperature sizing process. Compared with the existing polyvinyl alcohol (PVA) and polyacrylic acid (PAA) slurries, the desizing wastewater BOD5 / COD of the starch slurry is greater than 0.60, and it is highly biodegradable and eco-friendly. In addition, the slurry has strong anti-freezing properties and has the advantage of low-temperature sizing. By comparing the yarn quality of different types of slurries, the results show that the starch slurry used in this process greatly improves the breaking strength, elongation at break, abrasion resistance, abrasion resistance and other indicators of the yarn.

[0066] The above embodiments are only the best examples, and are not intended to limit the implementation of the present invention. In addition to the above embodiments, the present invention has other implementations. Any technical solution formed by equivalent replacement or equivalent transformation falls within the protection scope required by the present invention.

Claims

1. A preparation method of easily degradable corn starch slurry and a low-temperature sizing process, characterized in that The process includes the following steps: Step 1, adding corn starch, viscosity reducer and water into a high-pressure slurry mixing device; Cover the high-pressure mixing barrel, turn on the agitator to 950-970r / min, and simmer the slurry for a certain period of time at the set temperature and pressure; after the simmering is completed, enter the normal pressure mixing barrel; Step 2, adding a sizing accelerator to a normal pressure slurry mixing device, adjusting the stirrer to 170-190 r / min, and stirring to obtain the target starch slurry; Step 3: Input starch slurry into the sizing machine. During the yarn sizing process, control the sizing tank temperature to 75-85°C and the sizing machine speed to 80-90 m / min. After the sizing is completed, the finished yarn is obtained.

2. The preparation and low-temperature sizing process of a readily degradable corn starch slurry according to claim 1, characterized in that: In step 1, the mass ratio of corn starch, viscosity reducer and water is 3.75-11.25:0-0.008:95-100.

3. The preparation and low-temperature sizing process of a readily degradable corn starch slurry according to claim 1, characterized in that: The viscosity reducing agent in step 1 is one or more of amylase, persulfate, hydrogen peroxide and hypochlorite.

4. The preparation of a readily degradable corn starch slurry and a low-temperature sizing process according to claim 1, 2 or 3, characterized in that: The temperature and pressure set in step 1 are 116-120° C. and 0.18-0.22 MPa, respectively.

5. The preparation and low-temperature sizing process of a readily degradable corn starch slurry according to claim 4, characterized in that: The duration of simmering in step 1 is 25-35 minutes.

6. The preparation of a readily degradable corn starch slurry and a low-temperature sizing process according to claim 1, characterized in that: The sizing accelerator in step 2 includes 20-40 parts of glycerol, 6-8 parts of palm oil, 1-5 parts of wax flakes, 2-3 parts of sodium alginate, 3-4 parts of carboxymethyl β-cyclodextrin, 20-40 parts of fatty alcohol polyoxyethylene ether and 5-15 parts of silicone compound.

7. The preparation of a readily degradable corn starch slurry and a low-temperature sizing process according to claim 1, characterized in that: The raw material of the yarn in step 3 is cotton or polyester-cotton.

8. The preparation of a readily degradable corn starch slurry and a low-temperature sizing process according to claim 7, characterized in that: In step 3, the viscosity of the slurry is also controlled to be 19-21 mPa·s. The sizing rate is 3-8%, the moisture regain of the sizing yarn is 10-15%, and the pressure of the sizing machine is 30-50KN.

9. The preparation of a readily degradable corn starch slurry and a low-temperature sizing process according to claim 7 or 8, characterized in that: The obtained sizing yarn has a sizing coverage of 20-25% and a penetration of 40-45%.

10. A finished yarn product, characterized in that: The finished product is obtained by adopting the sizing process described in any one of claims 1 to 8.

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