Polyester base cloth for waterproof coiled material and preparation method of polyester base cloth

Abstract

The invention relates to polyester base cloth for a waterproof roll and a preparation method of the polyester base cloth, and belongs to the technical field of non-woven materials. The polyester base fabric for the waterproof coiled material comprises the following components in percentage by mass: 80-85% of polyester filament spun-bonded needle-punched non-woven fabric and 15-20% of cassava starch glue coated on the surface of the polyester filament spun-bonded needle-punched non-woven fabric. The polyester base fabric for the waterproof coiled material is prepared by coating a polyester filament spun-bonded needle-punched non-woven fabric with cassava starch glue and drying the polyester filament spun-bonded needle-punched non-woven fabric. By utilizing the low-temperature gelatinization characteristic of cassava starch, the impregnation temperature is reduced, and the heat energy consumption is reduced; the viscosity and penetration depth of cassava starch glue are balanced by adjusting the solid content of cassava starch steeping liquor, and the stability of the preparation process of the polyester base cloth for the waterproof roll is improved; by utilizing the characteristic of high amylopectin content in cassava starch, starch glue with a loose gel network is formed on the surface of the polyester base cloth for the waterproof roll, so that the flexibility and the anti-aging characteristic of the starch glue are improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of non-woven materials, in particular to a polyester base fabric for waterproofing membrane and a preparation method thereof. BACKGROUND

[0002] In the current polyester base fabric, corn starch glue is often used for the adhesion and reinforcement of the polyester base fabric, so as to provide stiffness and tensile strength for the base.

[0003] However, corn starch glue generally has the disadvantages of low initial viscosity, high gelatinization temperature and low elongation at break of the glue film, thus causing poor process compatibility and high energy consumption in the manufacturing process of the polyester base fabric, and the prepared polyester base fabric product has the problems of brittle glue film and low elongation.

[0004] 1. Poor process compatibility: the viscosity of corn starch glue is prone to fluctuation, and the glue amount is uneven during high-speed impregnation (> 12 m / min), which requires frequent process adjustment;

[0005] 2. High energy consumption: corn starch gelatinization requires high temperature (75-85℃), and the energy consumption of steam heating is high;

[0006] 3. Brittle glue film and low elongation: corn starch glue has high crystallinity of amylose, which results in brittle glue film and low elongation of the base fabric. SUMMARY

[0007] Therefore, the present application provides a polyester base fabric for waterproofing membrane, which uses cassava starch mainly composed of amylopectin, which is easy to form a three-dimensional network structure, and has high initial viscosity and low-temperature gelatinization characteristics. Cassava starch is used to replace corn starch to prepare starch glue solution, which is used for the adhesion and reinforcement of the polyester base fabric in the production process of the polyester filament base fabric, so as to solve the problems of high energy consumption, brittle glue film and low elongation of the base fabric caused by corn starch glue, while maintaining the mechanical properties and aging resistance of the base fabric.

[0008] To achieve the above-mentioned purpose, the present application adopts the following technical solutions.

[0009] In a first aspect, the present application provides a preparation method of a polyester base fabric for waterproofing membrane, comprising the following steps:

[0010] Step 1: crystallizing and drying polyester chips, then melt extruding, filtering and metering; then spinning, cooling and drawing, and laying silk to obtain a networked non-woven fabric;

[0011] Step 2: needle punching the non-woven fabric for reinforcement, and controlling the thickness of the needle punched reinforced product by hot rolling to obtain a polyester filament spun-bonded needle punched non-woven fabric;

[0012] Step 3, impregnating the polyester filament spun-bonded needle-punched non-woven fabric with the cassava starch impregnating solution, and then carrying out a rotary screen drying, so as to form a cassava starch layer on the surface of the polyester filament spun-bonded needle-punched non-woven fabric, and obtain the polyester base fabric for waterproofing membrane.

[0013] Optionally, in the step 1, the drying temperature is 165-175℃ (for example, 170℃).

[0014] In the present application, the polyester chip is dried after crystallization to remove the water in the polyester chip.

[0015] Optionally, in the step 1, the melt extrusion is carried out in a screw extruder, the temperature of the first zone of the screw extruder is 274-276℃, the temperature of the second zone is 279-281℃, the temperature of the third zone is 284-286℃, the temperature of the fourth zone is 287-289℃, the temperature of the fifth zone is 285-287℃, and the temperature of the sixth zone is 284-286℃.

[0016] Preferably, in the step 1, the melt extrusion is carried out in a screw extruder, the temperature of the first zone of the screw extruder is 275℃, the temperature of the second zone is 280℃, the temperature of the third zone is 285℃, the temperature of the fourth zone is 288℃, the temperature of the fifth zone is 286℃, and the temperature of the sixth zone is 285℃.

[0017] Optionally, in the step 1, in the cooling and filament-spreading process, side blowing is used for cooling, and the air temperature of the side blowing is 20℃.

[0018] Optionally, in the step 2, the needle punching density is 30-40 needles / cm 2 (for example, 35 needles / cm 2 ), and the needle punching depth is 8-10mm (for example, 9mm).

[0019] Optionally, in the step 2, in the hot rolling process, the temperature of the compression roller is 0-225℃ (for example, 50℃, 100℃, 150℃ or 200℃), and the pressure is 0-70bar (for example, 20bar, 40bar or 50bar).

[0020] Optionally, in the step 3, in the impregnation process, the impregnation temperature is 60-65℃ (for example, 62℃ or 64℃).

[0021] In the present application, the cassava starch has the feature of low-temperature gelatinization to form cassava starch glue, and thus the stability of the cassava starch impregnation solution is controlled by using the low-temperature gelatinization feature. Specifically, the cassava starch contains about 83wt% amylopectin, and the highly branched molecular structure of the amylopectin enables the cassava starch to be quickly gelatinized at a low temperature of 60-65℃. The short-chain structure of the amylopectin quickly combines with water molecules during gelatinization, and a hydrogen bond network is quickly formed to obtain a uniform colloid. The hydrogen bond network can avoid the molecular chain breakage caused by high temperature. Compared with the gelatinization temperature of corn starch (75-85℃), the use of the cassava starch impregnation solution instead of the corn starch impregnation solution for impregnation finishing can reduce the energy consumption of the preparation process of the polyester base fabric by more than 20%.

[0022] In addition, the cassava starch reaches complete gelatinization at 85℃ / 15min, while the corn starch needs 95℃ / 20min to reach complete gelatinization. Therefore, the use of the cassava starch instead of the corn starch can save a lot of production cost. Moreover, the initial viscosity of the cassava starch glue is high, the initial bonding speed is fast, and the viscosity fluctuation is small.

[0023] Optionally, in the step 3, the impregnation pressure during the impregnation finishing process is 0.9-1.1bar (for example, 1.0bar).

[0024] Optionally, in the step 3, the solid content of the cassava starch impregnation solution during the impregnation finishing process is 6-7wt%.

[0025] Optionally, in the step 3, during the circular net drying process, the first zone is 120-130℃; the second zone is 130-140℃; the third zone is 170-180℃; and the fourth zone is 170-180℃.

[0026] Optionally, in the step 3, the circular net drying is eight circular net drying.

[0027] In the present application, the cassava starch is used as the adhesive. The high amylopectin content structure in the cassava starch is beneficial to the anti-retrogradation (aging) property of the starch glue. The specific reasons are as follows:

[0028] (1) Molecular chain steric hindrance effect: The branched structure of the amylopectin naturally hinders the ordered arrangement of the molecular chain, inhibits the retrogradation (aging), and makes the viscosity fluctuation of the cassava starch glue within 8 hours be less than ±5%, while the viscosity fluctuation of the corn starch glue is ±15%;

[0029] (2) Low amylose content is beneficial to maintaining the stability of the starch glue: The amylose content in the cassava starch is only 17wt%, which is lower than the 25-28wt% amylose content in the corn starch. The amylose content reduces the tendency of molecular chain rearrangement and crystallization, and maintains the stability of the starch glue.

[0030] In addition, the cassava starch is used as the adhesive in the present application, and the high amylopectin content in the structure of the cassava starch is beneficial to the formation of a loose gel network of the starch glue, and the flexibility of the starch glue is improved; the specific reasons are as follows:

[0031] (1) Three-dimensional porous structure: compared with amylose, the gel network formed by amylopectin has higher porosity, which gives the starch glue film natural flexibility (i.e., excellent elongation), for example, the elongation of the glue film of the cassava starch glue is about 15%, and the elongation of the glue film of the corn starch glue is about 10%;

[0032] (2) Enhanced fiber wrapping: the porous structure of the cassava starch makes the cassava starch glue more easily penetrate into the gap of the polyester filament spun-bonded needle-punched non-woven fabric, and the bonding force between the polyester fiber and the cassava starch glue is improved through physical anchoring.

[0033] In the second aspect, the present application provides a polyester base fabric for waterproofing membrane, which is prepared by the above-mentioned method for preparing the polyester base fabric for waterproofing membrane, and contains 80-85wt% of polyester filament spun-bonded needle-punched non-woven fabric and 15-20wt% of cassava starch layer, wherein the cassava starch layer is arranged on the surface of the polyester filament spun-bonded needle-punched non-woven fabric.

[0034] Optionally, the grammage of the polyester filament spun-bonded needle-punched non-woven fabric is 250-256g / m 2 .

[0035] Optionally, the content of amylopectin in the cassava starch in the cassava starch layer is 83-85wt%.

[0036] In the present application, the cassava starch structure contains 83-85wt% of amylopectin, which is easy to form a three-dimensional network structure, which gives the cassava starch glue (or cassava starch glue body) high viscoelasticity and shear thinning properties.

[0037] Optionally, the elongation at break of the glue film of the cassava starch glue formed by the cassava starch can reach 25-30%.

[0038] In the present application, the elongation at break of the glue film of the cassava starch glue can reach 25-30%, which is much larger than the elongation at break of the glue film of the corn starch glue formed by corn starch, which is 15-20%, and thus the polyester base fabric product prepared by coating the cassava starch glue on the polyester filament spun-bonded needle-punched non-woven fabric to form a glue film (i.e., gluing by impregnation finishing) has a corresponding more excellent elongation at break.

[0039] In the present application, the above technical features can be freely combined to form new technical solutions without conflict.

[0040] Compared with the prior art, the technical scheme has the following beneficial technical effects:

[0041] (1) The preparation method of the polyester base fabric for waterproofing membrane provided by the present application reduces the impregnation temperature to below 65 DEG C by utilizing the low-temperature gelatinization characteristics of cassava starch, reduces the gelatinization temperature by 15-20 DEG C compared with the impregnation process temperature (above 75 DEG C) of traditional corn starch glue, reduces the heat energy consumption, and saves energy by about 22%;

[0042] (2) The preparation method of the polyester base fabric for waterproofing membrane provided by the present application balances the viscosity and penetration depth of cassava starch glue by adjusting the solid content (6-7%) of the cassava starch impregnation solution, the viscosity fluctuation of the cassava starch glue is less than or equal to ± 5%, and the CV value of the glue amount is less than or equal to 4.5%, thereby improving the stability of the preparation process of the polyester base fabric for waterproofing membrane;

[0043] (3) The preparation method of the polyester base fabric for waterproofing membrane provided by the present application adopts the eight-cylinder four-zone drying (130 DEG C→140 DEG C→170 DEG C→180 DEG C) of gradient drying design, which is suitable for the characteristics of the glue film of cassava starch glue, and avoids the cracking of the glue film of cassava starch glue caused by high-temperature sudden heating;

[0044] (4) The preparation method of the polyester base fabric for waterproofing membrane provided by the present application reduces the production cost by 10-12% compared with the preparation process of traditional polyester base fabric for waterproofing membrane;

[0045] (5) The polyester base fabric for waterproofing membrane provided by the present application utilizes the characteristics of high content of high-branched amylopectin in cassava starch to form a starch glue with loose gel network, thereby improving the flexibility and anti-aging characteristics of the starch glue; compared with the same type of corn starch adhesive product, the longitudinal elongation rate of the product can be improved by 3-5%, effectively improving the elongation rate of the product. DETAILED DESCRIPTION

[0046] In order to make the purpose, technical scheme and advantages of the embodiments of the present application more clear, the technical scheme in the embodiments of the present application is described clearly and completely below. Obviously, the described embodiments are part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor belong to the scope of protection of the present application.

[0047] Unless otherwise specifically defined, the terms used herein are understood as having the meanings commonly used in the art. Therefore, unless otherwise defined, all technical and scientific terms used herein have the same meanings as generally understood by those skilled in the art to which the present application belongs. If there is a conflict, the present specification takes precedence.

[0048] Example 1

[0049] A method for preparing a polyester-based fabric for waterproof membrane includes the following steps.

[0050] Step S1 involves crystallizing and drying the polyester chips, followed by melt extrusion, filtration, and metering; then spinning, cooling and drawing, and web laying to obtain a nonwoven fabric. Specifically, step S1 includes the following steps:

[0051] S11. Add polyester chips to the main feed hopper, remove moisture from the chips by crystallization and drying, and then melt them in a screw extruder; wherein the drying temperature is 165℃~175℃.

[0052] S12. In the screw extruder, the mixed polyester chips are melt-extruded. The temperature of the screw extruder is 275℃ in zone 1, 280℃ in zone 2, 285℃ in zone 3, 288℃ in zone 4, 286℃ in zone 5, and 285℃ in zone 6. After the melt is filtered by a filter and metered by a metering pump, it enters the spinning box for spinning. After being cooled by side blowing (air temperature: 20℃), it is transported to the splitting plate by the drawing tube. After splitting on the splitting plate, it is evenly spread onto the forming screen.

[0053] Step S2: The nonwoven fabric is needle-punched for reinforcement, and the thickness of the needle-punched reinforced product is controlled by hot rolling.

[0054] Specifically, the nonwoven fabric web is reinforced with a needle punch to give it a certain strength; the typical needle punch density is 35 needles / cm². 2 The needle-punching depth is 9mm. The thickness of the needle-punched and reinforced product is controlled by hot rolling using online thickness control equipment. The temperature of the pressure roller is generally 0~225℃, and the pressure is 0~70bar.

[0055] Step S3: Impregnate the needle-punched and reinforced nonwoven fabric with cassava starch impregnation solution, and then perform gradient drying using a circular wire drying process to form a cassava starch layer on the surface of the polyester filament spunbonded needle-punched nonwoven fabric, thereby obtaining a polyester base fabric for waterproof rolls.

[0056] Specifically, step S31, the preparation method of cassava starch impregnation solution (or bio-gel), includes the following steps:

[0057] (1) Prepare raw materials: 200 kg of cassava starch and 2.58 cubic meters of water;

[0058] (2) Preparation process:

[0059] ① Turn on the stirring motors of the mixing tank and the storage tank;

[0060] ② Add water by pressing "Water Pump" until the scale reaches the required 2.58 cubic meters;

[0061] ③Add starch, stir for 15 minutes;

[0062] ④Using steam heating, slowly warm up to 60-65℃, keep for 10 minutes to complete gelatinization.

[0063] Step S32, impregnate the needle reinforced product prepared in step S2 in the prepared cassava starch impregnation solution using a dip coater, wherein the pressure of the dip coater is about 1 bar.

[0064] Step S33, gradient dry the impregnated nonwoven fabric using an eight-cylinder drying oven, wherein the first zone is 120-130℃; the second zone is 130-140℃; the third zone is 170-180℃; and the fourth zone is 170-180℃.

[0065] Step S4, appearance inspection is performed on the product prepared in step S3, the product is slit (or edge cut) according to the needs of customers to obtain products with different widths, and the products are packaged.

[0066] Example 2

[0067] A preparation method of a polyester base fabric for waterproofing membrane, which is prepared by the preparation method of Example 1; the solid content of the cassava starch impregnation solution is 6.3%, and the polyester base fabric for waterproofing membrane prepared has a glue content of 21wt%.

[0068] Table 1 lists the gelatinization temperature of cassava starch and the corresponding viscosity table, and Table 2 lists the grammage and performance indicators of the polyester base fabric for waterproofing membrane prepared in the example (samples taken 3 times, denoted as samples ①, ② and ③). The test method of the performance indicators refers to GB / T18840-2018. The gelatinization viscosity detection method of cassava starch and corn starch refers to the national standard GB / T12309-90. An intelligent constant temperature magnetic stirrer and a rotary viscometer are used to perform the gelatinization experiment of cassava starch and corn starch.

[0069] Table 1 Gelatinization temperature of cassava starch and corresponding viscosity table

[0070]

[0071] Table 2 Grammage and performance indicators of the polyester base fabric for waterproofing membrane in Example 2

[0072]

[0073] Comparative Example 1

[0074] A preparation method of a polyester base fabric for waterproofing membrane, which is different from Example 2 in that a corn starch impregnation liquid with a solid content of 6.3% is used instead of the cassava starch impregnation liquid with a solid content of 6.3% to prepare the polyester base fabric for waterproofing membrane with a glue content of 21wt%. Table 3 lists the gelatinization temperature of corn starch and the corresponding viscosity table, and Table 4 lists the grammage and performance indicators of the polyester base fabric for waterproofing membrane prepared in this comparative example (samples taken 3 times, respectively, denoted as samples ①, ②, ③).

[0075] Table 3 Gelatinization temperature of corn starch and corresponding viscosity table

[0076]

[0077]

[0078] Table 4 Grammage and performance indicators of the polyester base fabric for waterproofing membrane in Comparative Example 1

[0079]

[0080] Example 3

[0081] A preparation method of a polyester base fabric for waterproofing membrane, which uses the same method as Example 2 to prepare the polyester base fabric for waterproofing membrane, and is different from Example 2 in that the glue content of cassava starch glue in the prepared polyester base fabric for waterproofing membrane is 25wt%.

[0082] Table 5 lists the grammage and performance indicators of the polyester base fabric for waterproofing membrane prepared in this example (samples taken 3 times, respectively, denoted as samples ①, ②, ③).

[0083] Table 5 Grammage and performance indicators of the polyester base fabric for waterproofing membrane in Example 3

[0084]

[0085] Example 4

[0086] A preparation method of a polyester base fabric for waterproofing membrane, which uses the same method as Example 2 to prepare the polyester base fabric for waterproofing membrane, and is different from Example 2 in that the glue content of cassava starch glue in the prepared polyester base fabric for waterproofing membrane is 25wt%.

[0087] Table 6 Grammage and performance indicators of the polyester base fabric for waterproofing membrane in Example 4

[0088]

[0089] Result analysis

[0090] A comparison of Tables 1 and 3 shows that the gelatinization peak temperature of corn starch is around 89℃, with a corresponding gelatinization peak viscosity of 1526; while the gelatinization peak temperature of cassava starch is around 67℃, with a corresponding gelatinization peak viscosity of 2339.5. Although the gelatinization temperature of cassava starch is much lower than that of corn starch, the corresponding gelatinization viscosity is much higher, which reflects the high branching characteristics of cassava starch and its low-temperature and high-efficiency gelatinization characteristics.

[0091] A comparison of Tables 2 and 4 shows that, when using cassava starch adhesive and corn starch adhesive with the same solid content to prepare polyester base fabric for waterproof membranes, the elongation of the polyester base fabric obtained after impregnation with cassava starch adhesive is significantly higher than that obtained after impregnation with corn starch adhesive when the adhesive content in the prepared polyester base fabric is the same (21 wt% in both Example 1 and Comparative Example 1). This is because cassava starch contains 83 wt% to 85 wt% amylopectin, which easily forms a three-dimensional network structure, thus giving the colloid high viscoelasticity and shear dilution properties. The elongation at break of the cassava starch adhesive film can reach 25% to 30%, which is much greater than the 15% to 20% of corn starch.

[0092] As can be seen from Tables 5 and 6, the basis weight and performance indicators of the polyester base fabric for waterproof membranes with cassava starch adhesive content of 25wt% and 30wt% can meet the customer requirements for polyester base fabrics used in waterproof membranes.

[0093] The above description is merely a specific embodiment of the present invention, enabling those skilled in the art to understand or implement the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the present invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features claimed herein.

Claims

1. A method for preparing a polyester base fabric for waterproof membranes, characterized in that, Includes the following steps: Step 1: Crystallize and dry the polyester chips, then melt extrude, filter, and meter them; then spin, cool and stretch, and lay the yarn into a web to obtain a nonwoven fabric. Step 2: Needle-punch the nonwoven fabric and control the thickness of the needle-punched reinforced product by hot rolling to obtain polyester filament spunbond needle-punched nonwoven fabric. Step 3: Impregnate the polyester filament spunbond needle-punched nonwoven fabric with cassava starch impregnation solution, and then dry it with a circular screen to form a cassava starch layer on the surface of the polyester filament spunbond needle-punched nonwoven fabric, and obtain the polyester base fabric for the waterproof roll material.

2. The method for preparing the polyester base fabric for waterproof membrane according to claim 1, characterized in that, In step 1, the drying temperature is 165℃~175℃.

3. The method for preparing the polyester base fabric for waterproof membrane according to claim 1, characterized in that, In step 1, melt extrusion is carried out in a screw extruder. The temperature of the screw extruder is 274-276℃ in zone 1, 279-281℃ in zone 2, 284-286℃ in zone 3, 287-289℃ in zone 4, 285-287℃ in zone 5, and 284-286℃ in zone 6.

4. The method for preparing the polyester base fabric for waterproof membrane according to claim 1, characterized in that, In step 1, during the cooling and stretching process, side-blowing air is used for cooling.

5. The method for preparing the polyester base fabric for waterproof membrane according to claim 1, characterized in that, In step 2, the needle density is 30-40 needles / cm². 2 The needle insertion depth is 8–10 mm; or / and In step 2, the temperature of the pressure rollers during the hot rolling process is 0–225°C, and the pressure is 0–70 bar.

6. The method for preparing the polyester base fabric for waterproof membranes according to any one of claims 1-5, characterized in that, In step 3, during the impregnation process, the impregnation temperature is 60-65℃ and the impregnation pressure is 0.9-1.1 bar.

7. The method for preparing the polyester base fabric for waterproof membrane according to claim 6, characterized in that, In step 3, during the impregnation and finishing process, the solid content of the cassava starch aqueous solution is 6-7 wt%.

8. The method for preparing the polyester base fabric for waterproof membrane according to claim 6, characterized in that, In step 3, during the rotary screen drying process, the temperature in the first zone is 120-130℃; the temperature in the second zone is 130-140℃; the temperature in the third zone is 170-180℃; and the temperature in the fourth zone is 170-180℃.

9. A polyester base fabric for waterproof membranes, characterized in that, The waterproof membrane is prepared by the method of any one of claims 1-8, wherein the waterproof membrane comprises, by mass percentage, 80-85% polyester filament spunbond needle-punched nonwoven fabric and 15-20% cassava starch layer, wherein the cassava starch layer is disposed on the surface of the polyester filament spunbond needle-punched nonwoven fabric.

10. The polyester base fabric for waterproof membrane according to claim 9, characterized in that, The basis weight of the polyester filament spunbond needle-punched nonwoven fabric is 250-256 g / m². 2 ; The content of amylopectin in the cassava starch layer is 83-85 wt%. The elongation at break of the cassava starch adhesive film formed from the cassava starch can reach 25% to 30%.

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