CN121379110A

CN121379110A - A two-color molding process for shoemaking

Info

Publication number: CN121379110A
Application number: CN202511797443.2A
Authority: CN
Inventors: 陈同举; 常勋美
Original assignee: Dongguan Zhanfeng Sports Technology Co ltd
Current assignee: Dongguan Zhanfeng Sports Technology Co ltd
Priority date: 2025-12-02
Filing date: 2025-12-02
Publication date: 2026-01-23

Abstract

The invention discloses a double-color molding process for shoemaking, which belongs to the technical field of shoemaking and comprises the steps of S1, respectively preparing a first pigment and a second pigment, wherein the raw materials of the first pigment comprise a casting polyurethane elastomer, an isolated color paste and an anti-yellowing agent, the raw materials of the second pigment comprise PTMG, MDI, BDO, mica sheets, nanometer alumina, inorganic color paste, a silane coupling agent, a dispersing agent, an antioxidant and a toughening agent, S2, injection molding the first pigment, carrying out plasma treatment, S3, placing a first pigment product subjected to plasma treatment into a sole mold, accurately positioning, then injecting the second pigment into the sole mold, demolding after heat preservation vulcanization treatment and cooling, and forming a double-color sole, and S4, trimming and cleaning the double-color sole to obtain a final double-color sole product. The sole product has the advantages of high interface binding force, accurate double-color effect, excellent functional performance and appearance texture.

Description

Double-color forming process for shoemaking

Technical Field

The invention mainly relates to the technical field of shoemaking, in particular to a bicolor molding process for shoemaking.

Background

With the continuous upgrading of the functional and personalized demands of the sports shoes, the GCU (thermosetting polyurethane elastomer composite) sole with wear-resistant and anti-slip properties becomes a research and development hot spot in the industry. The GCU material is widely applied to core functional areas such as soles and the like because of excellent tearing strength, dynamic anti-skid performance and weather resistance. Sole products combining GCU materials with EVA (ethylene-vinyl acetate copolymer) or supercritical foaming midsoles have appeared in the prior art, such as a GCU sole and a GCU outsole and midsole integrated molding preparation method disclosed in patent CN118876308A, the prefabricated EVA or supercritical midsole is placed in a die, the GCU material is poured into the die, and the GCU material is heated and vulcanized in vacuum, so that the integrated forming of the GCU outsole and the midsole is realized, the problems of layering and degumming in the traditional bonding process are primarily solved, and meanwhile, the wear resistance and the skid resistance of the sole are improved by utilizing the GCU material.

In the field of double-color sole preparation, various integrated molding technical routes are formed in the industry. For example, the injection molding die and the production method thereof for the double-color shock-absorbing sole disclosed in the patent CN119408073A propose to adopt the process of step injection molding and movable die core control, firstly, the sole made of EVA material is molded by one-time injection molding, then the movable die core capable of moving vertically is utilized to adjust the die cavity, the side support gasket made of TPU (thermoplastic polyurethane) material is molded by two-time injection molding, the integral molding of double-color double-material is realized by air passage vacuumizing and temperature precise control, the defect of high labor cost and poor consistency of the traditional bonding process is avoided, the double-color double-density sole and the molding process thereof disclosed in the patent CN119699719A take the supercritical TPU as raw materials, the supercritical TPU beads with two different colors are synchronously injected by arranging the heatable and the fusible separating plate (hot melt adhesive film or TPU plate) in the die, and the fusion of a double-color interface is realized by utilizing the melting of the separating plate in the one-time physical foaming process, thereby solving the problems of obvious double-color boundary and poor fusion degree in the traditional step foaming.

Although the integrated molding of the bicolor or GCU sole is realized by the technology, the technology has obvious limitation in practical application, and the comprehensive requirements of high-end sport shoes on functional accuracy, interface firmness and appearance refinement are difficult to meet:

In the CN118876308A, the GCU material is naturally spread only through pouring, the optimal design is not carried out on the flow characteristic and the dispersibility of the GCU material, the thickness deviation of the GCU layer is easily caused by the uneven local pressure of a die cavity, the interface combination of the GCU and the EVA/supercritical midsole only depends on hot melt adhesion, the surface of a substrate is not subjected to active modification, the interface stripping is easy to occur under long-term dynamic stress (such as running and jumping), the stripping strength is usually lower than 2.5MPa, and the requirement of a high-strength sport scene cannot be met.

2. The defects of color channeling and forming precision of the bicolor interface are that in the step injection molding process of the CN119408073A, prevention and control are not designed aiming at pigment migration of two materials, color paste in primary injection EVA is easily diffused to cause bicolor boundary blurring due to high temperature during secondary injection molding of TPU, meanwhile, the positioning precision of a movable die core depends on a mechanical structure, a surface roughening process such as plasma treatment is not introduced, the physical occlusion effect of a first material and a second material is weak, and the interface shock resistance is insufficient.

3. The material function and the appearance performance are difficult to be compatible, the supercritical TPU is adopted as a single material system in the CN119699719A, the double density can be realized, but the surface glossiness of the supercritical TPU is low, the yellowing resistance is poor, the requirements of high-end products on appearance texture cannot be met, and meanwhile, trace impurities possibly remain after the partition plate is melted, the uniformity of the internal structure of the sole is influenced, and the wear resistance is fluctuated.

Based on the problems, the invention aims to solve the technical problems of uneven dispersion, unstable interface combination, double color channeling and the like of the GCU and double-color sole preparation technology in the prior art, and meets the comprehensive requirements of high-end sports shoes.

Disclosure of Invention

Aiming at the technical problem that the prior art solution is too single, the technical scheme of the invention provides a solution which is obviously different from the prior art, and mainly provides a double-color molding process for shoemaking, so that a sole product has high interface binding force, accurate double-color effect, excellent functional performance and appearance texture, and meets the comprehensive requirements of high-end sports shoes.

The technical scheme adopted for solving the technical problems is as follows:

A double-color molding process for shoemaking comprises the following steps:

s1, respectively preparing a first pigment and a second pigment:

the first color material comprises the following raw materials in parts by weight:

100 parts of a casting polyurethane elastomer (CPU);

2-4 parts of isolated color paste;

0.2-0.3 part of anti-yellowing agent.

The second pigment comprises the following raw materials in parts by weight:

100 parts of polytetrahydrofuran glycol (PTMG);

25-30 parts of diphenylmethane diisocyanate (MDI);

5-10 parts of 1, 4-Butanediol (BDO);

8-12 parts of mica sheets;

4-8 parts of nano alumina;

2.5-4 parts of inorganic color paste;

0.5-1 part of silane coupling agent;

0.2-0.8 part of dispersing agent;

0.1-0.5 part of antioxidant;

1.5-3 parts of toughening agent;

Wherein PTMG, MDI and BDO are raw materials of GCU elastomer matrix, mica sheet and nano alumina are raw materials of composite hard sheet layer, the GCU elastomer matrix is used as soft phase matrix imitating shell lamellar structure, and the composite hard sheet layer is used as hard phase matrix imitating shell lamellar structure.

S2, injection molding the first color material, and putting the first color material product into a plasma processor for processing, wherein the surface tension of the processed product is more than or equal to 40mN/m, so that the interface bonding activity with the sole main body can be improved, and the surface roughness Ra=0.8-1.2 mu m after processing can enhance physical occlusion;

S3, placing the first pigment product subjected to plasma treatment into a sole mould, accurately positioning with positioning accuracy of +/-0.02 mm, then injecting a second pigment into the sole mould, carrying out heat preservation and vulcanization treatment, cooling, demoulding, and forming a bicolor sole;

S4, trimming and cleaning the bicolor sole to obtain a final bicolor sole product.

In the prior art, the dual-material composite relies on physical hot-melt adhesion (such as the GCU of CN118876308A and EVA hot melt, and the separation plate of CN119699719A is melted), and chemical interface modification is not involved. It is widely believed by those skilled in the art that the CPU has low content of surface active groups (-OH, -NH) (conventionally <0.3mmol/m < 2 >), weak chemical reactivity with GCU (containing isocyanate groups), direct recombination is easily layered due to insufficient interfacial binding force, and a hard sheet layer (such as mica sheet and nano alumina) can further weaken the interface contact area, so that the peeling risk of the sole main body and another pigment product is increased. This inherent concern over interface compatibility allows technicians to actively circumvent the CPU and GCU compounding scheme. The invention improves the active groups on the surface of the CPU to be more than or equal to 0.7mmol/m < 2 > through plasma treatment, and bridges the CPU and the GCU through the silane coupling agent, thereby breaking the prejudice of the combination of the CPU and the GCU, and belonging to the untouched chemical modification thought in the field.

In the prior art, the color channeling prevention treatment of the double-color non-adhesive combination relies on physical isolation from a fixed partition plate to a movable mold core, and does not break through a mechanical blocking frame. It is widely recognized by those skilled in the art that the nature of bi-color channeling is that the physical diffusion of pigment molecules is blocked by either the mold structure or temporary spacers, and that the ability to diffuse is limited by chemical encapsulation from the pigment itself is never considered. The isolated color paste (polyurethane coated pigment) locks pigment molecules through the coating layer, and cannot migrate even at the high temperature of GCU vulcanization, so that the chemical prevention and control thought completely jumps out of the existing physical isolation technical framework.

In the prior art, the interface bonding only depends on a single mechanism, such as the fusion bonding of CN118876308A by GCU and the EVA surface fusion bonding, the self-adhesion of CN103009553A by EVA injection foaming, and the fusion crosslinking of CN116749435A by a third die cavity to form physical embedding. The skilled person never realizes that the interfacial binding force is enhanced by the dual of chemical bonding and physical roughening. According to the invention, through plasma treatment, the surface roughness Ra=0.8-1.2 mu m of the CPU is improved, physical occlusion is promoted, and a silane coupling agent is used for bridging-OH of the CPU and-NCO of GCU to form a chemical bond, so that the peeling strength is improved to be more than or equal to 3.0MPa. The dual reinforcement thought breaks through the knowledge of single means of chemistry or physics in the field.

In the prior art, the technical staff generally considers that the performances of wear resistance, shock absorption, shock resistance and the like of the sole can be met only through material composition adjustment or macro-partition design, and a complex bionic layered structure is not required to be introduced. This prejudice fundamentally blocks the innovative direction of structural bionics. The core logic of the person skilled in the art is that as long as the hardness, density and wear resistance of the two materials are different, the partition compounding can meet the functional requirement, and the microstructure design (such as lamellar) is not considered to further strengthen the performance synergy. The core of the shell-like layered structure in the application is the synergistic effect (hard layer impact resistance and soft layer energy absorption) of the soft phase matrix (GCU) and the oriented hard photo layer (mica/nano alumina), and the thought of determining the performance of the structure completely jumps out of the inherent framework of determining the performance of the components in the shoe making field.

Further, in step S1, the preparation of the first coloring material includes the following steps:

(1) Weighing a pouring polyurethane elastomer, and placing the pouring polyurethane elastomer in stirring equipment for stirring;

(2) Adding isolated color paste and anti-yellowing agent into stirring equipment according to a proportion;

(3) Controlling the parameters, namely, the temperature is 75-85 ℃, the rotating speed is 150-250rpm, and stirring is carried out for 10-20min, so as to obtain the first pigment.

Further, in step S1, the preparation of the second coloring material includes the following steps:

(1) Weighing polytetrahydrofuran glycol, diphenylmethane diisocyanate and 1, 4-butanediol according to a proportion, mixing for 15-25min at 60-80 ℃ to obtain a GCU elastomer matrix, and putting the GCU elastomer matrix into an extruder;

(2) Weighing mica sheets and nano alumina, mixing, and drying at 110-130 ℃ for 1-3 hours, then adding silane coupling agent accounting for 0.2% of the total amount of the mica sheets and the nano alumina, and uniformly mixing to obtain a hard sheet layer;

(3) Introducing the GCU elastomer matrix into an extruder melting section, controlling the temperature to be 190-200 ℃, and adding a hard sheet layer, a dispersing agent, inorganic color paste, a residual silane coupling agent, an antioxidant and a toughening agent after the GCU elastomer matrix is melted;

(4) Controlling extrusion temperature, namely, a feeding section 175+/-3 ℃, a melting section 195+/-5 ℃ and a head section 200+/-3 ℃, wherein the rotating speed of a screw is 250-350rpm, and the granulating particle size is 3-5mm, so as to prepare second pigment particles;

(5) And (3) drying the second pigment particles at 100-110 ℃ for 3.5-4.5 hours, wherein the water content of the pigment particles is less than or equal to 0.08%, so as to obtain the second pigment.

Further, the specific steps of step S2 are as follows:

(1) Preheating to 55-65 ℃ by adopting a die matched with the target shape of the first color material;

(2) Injecting the first color material into a mold, controlling the injection temperature to be 90-95 ℃, the injection pressure to be 48-55MPa, the injection speed to be 25-35mm/s, the holding pressure to be 35-45MPa and the holding time to be 8-12s;

(3) Cooling by a chiller at a temperature of 20 ℃ until the temperature of the cooling medium reaches 40+/-2 ℃, and demolding;

(4) The first color material product is put into a plasma processor, the power is controlled to be 480-520W, and the processing time is 25-35s.

Further, in the step S3, the sole mould is preheated to 80-90 ℃ firstly, and then the first color material product after plasma treatment is put in;

And/or the positioning precision of the accurate positioning is +/-0.02 mm.

Further, in the step S3, when the second pigment is injected into the sole mould, the casting temperature is controlled to be 95+/-3 ℃, the casting pressure is controlled to be 0.2-0.4MPa, and the casting speed is controlled to be 40-60mL/S;

and/or adopting step-by-step pouring, filling the sole mould cavity 1/3, stopping for 1-3s, and then filling to be full.

Further, in the step S3, the heat preservation and vulcanization treatment is that the heat preservation and vulcanization are carried out for 25-35min at the temperature of 95-105 ℃, and the temperature of the vulcanized product is reduced to 80+/-3 ℃ at the cooling rate of 2-3 ℃ per min in the later period of vulcanization;

And/or cooling to 60+ -2 deg.C at a rate of 3 deg.C/min and then to 50+ -2 deg.C at a rate of 2 deg.C/min.

Further, in the step S3, after demoulding, the sole is placed in a constant temperature and humidity environment with the temperature of 20-25 ℃ and the RH of 45-55% for 20-30 hours so as to stabilize the shell-like layered structure.

In step S4, trimming is to remove the overflow material at the edge of the sole, wherein the trimming precision is +/-0.1 mm, and the trimming direction is consistent with the layered arrangement direction during trimming, so that the main layered structure is prevented from being damaged.

Further, in the step S4, the sole surface is cleaned by using absolute ethyl alcohol to remove residual release agent, and the sole is naturally air-dried after cleaning.

Compared with the prior art, the invention has the beneficial effects that:

(1) The first pigment adopts the isolation type color paste coated by polyurethane, and the coating layer can prevent pigment molecules from migrating to the GCU matrix in the vulcanization process of the second pigment, and simultaneously, the process of precisely positioning the first pigment in the sole mold after preforming is matched, so that the accuracy of the double-color boundary is ensured. In the prior art, the color shifting cannot be prevented and controlled from the pigment molecular layer only by virtue of the physical isolation of the mold, but the source color shifting prevention is realized through the chemical coating, so that the appearance fineness of the double colors is obviously improved. The application achieves the effect that the double-color boundary is clear and has no color channeling by means of the action principle of physically locking pigment molecules and blocking pigment diffusion in the high-temperature vulcanization process by virtue of the coating layer, and solves the problems of easy color channeling and blurred boundary of industrial pain points in high-temperature molding of the double-color sole compared with the prior art.

(2) After plasma treatment, the surface tension of the first pigment product is raised to be more than or equal to 40mN/m, the wettability with GCU is obviously enhanced, the epoxy group of the silane coupling agent reacts with the-OH on the surface of the CPU, the siloxane group is crosslinked with the-NCO of the GCU to form double interface combination of physical occlusion and chemical bonding, and finally the interface peel strength and the impact strength of a simply supported beam are improved, so that the interface stability requirement under a high-strength sport scene can be met. The invention realizes physical occlusion by improving the surface active groups and the roughness of the CPU by means of the plasma, and the silane coupling agent bridges the action principle that-OH of the CPU and-NCO of GCU form chemical bonding, thereby achieving the effect of high peel strength of a bicolor interface.

(3) The second pigment for preparing the sole main body of the shoe adopts GCU elastomer (PTMG+MDI+BDO) as a soft phase matrix to ensure compression rebound rate, thereby optimizing the damping performance of the sole, and adding mica sheets and nano aluminum oxide composite hard sheets to form a shell-like layered structure, so that the wear resistance of the sole can be improved. And the first color material adopts CPU to mix color paste and anti-yellowing agent, and realizes better decorative effect through high-gloss die injection molding. The first pigment and the second pigment form a composite structure through injection molding, the inherent limitation that the abrasion resistance is required to be sacrificed when the gloss is required and the appearance is required to be abandoned when the function is required in the prior art is broken, and the dual requirements of texture and performance of the high-end sports shoes are met. The invention provides a synergistic action principle of decoration, GCU matrix guaranteeing elastic shock absorption and hard sheet strengthening wear resistance by means of CPU, achieves the effect of combining appearance and high functional performance, and solves the technical contradiction that the appearance and the function are necessary to be abandoned in the shoemaking field compared with the prior art.

(4) The method controls the shearing rate of the screw, ensures that the hard sheet layer is not excessively sheared, controls the flow front speed of the feed liquid, ensures the orientation consistency of the sheet layer, and avoids internal stress of an interface caused by temperature difference by cooling step by step. The dimensional accuracy of the final product is controlled to be +/-0.03 mm, the qualification rate of the layered structure is more than or equal to 99.5%, the cognitive limit that the prior art macroscopic process cannot control the microstructure is broken through, and the industrialized mass production of the bionic structure is realized. The invention achieves the effects of stable mass production and high dimensional accuracy of the shell-like layered structure by means of the action principle of precisely controlling the morphology of the lamellar, avoiding the internal stress between the lamellar and stabilizing the layered structure.

(5) The invention prevents the sheet from being damaged by controlling the shearing rate of the screw rod, controls the flow front speed of the feed liquid to guide the orientation of the sheet, leads the hard sheet to be arranged in parallel along the stress direction of the sole, and forms the hard impact-resistant and soft energy-absorbing structure of the shell-like pearl layer, wherein the hard sheet can resist the friction and impact of the ground, the soft phase GCU matrix can absorb the impact force of movement, and the performance limitation that the prior art has the defects of improving the abrasion resistance, reducing the shock absorption, enhancing the shock absorption and sacrificing the abrasion resistance is broken. The invention achieves the effect of cooperatively improving the wear resistance and the shock absorption performance by means of the synergistic action principle of the soft phase GCU matrix energy absorption and buffering of which the hard sheet layers are parallel to the stress direction and the interlayer spacing is 5-10 mu m, and compared with the prior art, the invention solves the performance defect that the wear resistance and the shock absorption of the sole are difficult to be compatible.

(6) The second pigment adopts a step pouring mode of filling the cavity 1/3 first and stopping for a few seconds to be refilled to full, so that interface bubbles caused by direct impact of feed liquid on the CPU preformed piece are avoided, and the GCU matrix can be fully crosslinked and the hard sheet layer is stable in position in the standing process after demolding, so that performance fluctuation is reduced. In the prior art, the foam is directly delivered after one-time filling or foaming, so that the defective rate is high due to bubbles and unstable structure, and the defective rate is reduced through process optimization, so that the economical efficiency of mass production is remarkably improved. The invention adopts the action principle of filling cavities step by step to prevent feed liquid from impacting the CPU preformed piece and stabilizing the layered structure at constant temperature and humidity, thereby achieving the effects of no bubble and stable performance of the product.

The invention will be explained in detail below with reference to the drawings and specific embodiments.

Drawings

FIG. 1 is a process flow diagram of the present invention;

Fig. 2 is a product diagram of a first embodiment of the present invention.

Detailed Description

In order that the invention may be more fully understood, a more particular description of the invention will be rendered by reference to the appended drawings, in which several embodiments of the invention are illustrated, but which may be embodied in different forms and are not limited to the embodiments described herein, which are, on the contrary, provided to provide a more thorough and complete disclosure of the invention.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly connected to one of ordinary skill in the art to which this invention belongs, and the knowledge of terms used in the description of this invention herein for the purpose of describing particular embodiments is not intended to limit the invention, and the term "and/or" as used herein includes any and all combinations of one or more of the associated listed items.

Referring to fig. 1, the embodiment one provides a dual-color molding process for shoemaking, comprising the following steps:

1. Raw material preparation

1. The first color material comprises 100 parts of high-gloss CPU (Basf 1185A) with water content less than or equal to 0.1%, 3 parts of isolated color paste (coated pigment, polyurethane coating and organic violet pigment) with solid content of 30-35%, and 0.2 part of anti-yellowing agent UV-327, wherein the parts of all the substances are based on 100 parts of the high-gloss CPU;

2. The second pigment comprises a GCU elastomer matrix (PTMG 100 parts, MDI28 parts and BDO7 parts), a composite hard sheet layer (mica sheet 10 parts, nano alumina 6 parts, the grain diameter of 100-150 meshes and the sheet diameter-thickness ratio of 45:1), 3.2 parts of inorganic color paste (carbon black pigment), 0.6 part of a silane coupling agent KH-560, 0.4 part of a dispersing agent BYK-966, 0.3 part of an antioxidant 1010 and 2 parts of a toughening agent EVA-g-MAH, wherein the parts of each substance are based on 100 parts of PTMG.

2. Preparation of two colorants

1. The preparation of the first pigment comprises the following steps:

(1) Weighing CPU particles (Basoff 1185A), and placing into a vacuum stirrer;

(2) Adding isolated color paste and anti-yellowing agent into a vacuum stirrer according to the proportion;

(3) The control parameters are that the temperature is 80 ℃, the rotating speed is 200rpm, the vacuum degree is-0.09 MPa, and the stirring is carried out for 15min, wherein the material liquid after stirring has no macroscopic color point, no bubbles and no macroscopic auxiliary agent particles;

(4) Transferring into a charging barrel of a CPU injection molding machine, and preserving heat at the temperature of 85 ℃ for standby.

2. The preparation of the second pigment comprises the following steps:

(1) Weighing PTMG, MDI, BDO according to a proportion, mixing for 20min in a 70 ℃ vacuum stirrer, controlling the viscosity of the prepolymer to be 800-1000mPa & s at 25 ℃ to obtain a GCU elastomer matrix, and placing the GCU elastomer matrix into a feeding section 1 of a double-screw extruder;

(2) Mixing mica sheets and nano alumina according to the proportion of 5:3, and drying at 120 ℃ for 2 hours, then adding KH-560 accounting for 0.2% of the total amount of the mica sheets and the nano alumina, and uniformly mixing to obtain a hard sheet layer, wherein the water content of the composite hard sheet layer is less than or equal to 0.05%, the KH-560 uniformly coats the surface of the sheet layer, and the compatibility with a soft phase matrix is enhanced;

(3) Feeding the GCU elastomer matrix into a melting section of an extruder, controlling the temperature to be 195 ℃, adding a hard sheet layer and a dispersing agent BYK-966 from a side feeding port after the GCU elastomer matrix is melted, adding inorganic color paste, residual KH-560, an antioxidant 1010 and a toughening agent EVA-g-MAH into a machine head section, controlling the temperature of the side feeding port to be 190 ℃, avoiding high-temperature decomposition of the hard sheet layer, and ensuring the orientation effect;

(4) The extrusion temperature is controlled, the feeding section is 175 ℃, the melting section is 195 ℃, the head section is 200 ℃, the screw rotating speed is 300rpm, the granulating grain diameter is 3-5mm, the shear rate of the screw is 110s ^-1 measured under the conditions that the material temperature is 195 ℃ and the depth of a screw groove is 3mm, the second pigment grain is prepared, the shear rate of the screw is precisely controlled, the hard sheet layer is prevented from being excessively sheared and damaged, the diameter-thickness ratio is kept to be more than or equal to 40:1, and the grains do not need to be obviously agglomerated after granulating;

(5) Drying the second pigment particles at 105 ℃ for 4 hours, wherein the water content of the pigment particles is less than or equal to 0.08%, transferring the pigment particles into a pouring system material tank, preserving heat at 90 ℃ and stirring the material liquid at 55rpm, carrying out low-speed stirring in a heat preservation stage to prevent the settlement of hard lamellar layers, and pre-orienting the material liquid lamellar structure (the stirring direction is consistent with the flow direction of the subsequent pouring).

3. Injection molding

1. The first color material injection molding comprises the following steps:

(1) Adopting a mould matched with the target shape of the first color material, preheating to 60 ℃ and carrying out highlight treatment on a cavity, wherein the cavity of the mould needs to be clean and free of impurities, so that the surface glossiness of the decorating part is prevented from being influenced;

(2) Injecting the first color material into a mold, controlling the injection temperature to be 90-95 ℃, the injection pressure to be 50MPa, the injection speed to be 30mm/s, and the holding pressure to be 40MPa, wherein the holding time to be 10s;

(3) Cooling by a chiller at a temperature of 20 ℃ and a cooling medium at a cooling rate of 3 ℃ per minute to 40 ℃ and demolding, wherein the cooling rate is less than or equal to 5 ℃ per minute, and the cooling rate is uniform, so that internal stress and uneven color of a first pigment product due to overlarge temperature difference are avoided;

(4) Checking a first pigment product, wherein the color is uniform (delta E is less than or equal to 0.7), the surface is free from bubbles or burrs, the dimensional accuracy is +/-0.03 mm, and the surface active group content is more than or equal to 0.7mmol/m ²;

(5) The qualified first color material product is placed into a plasma processor, the control parameters are that the power is 500W, the processing time is 30s, the gas flow is 20L/min, the gas is mixed gas of argon and oxygen according to the ratio of 9:1, the surface tension of the processed product is more than or equal to 40mN/m, the interface bonding activity with a sole main body can be improved, and the surface roughness Ra=0.8-1.2 mu m after the processing can enhance physical occlusion.

2. The second pigment injection molding comprises the following steps:

(1) Preheating a sole mould to 85 ℃ to enable the temperature of the mould to be matched with the heat preservation temperature of the second pigment, so that the influence of rapid cooling after the contact of feed liquid on the forming of the layered structure is avoided;

(2) Placing the first color material product after plasma treatment into a sole mold, and accurately positioning according to the design position, wherein the positioning precision is +/-0.02 mm;

(3) Injecting a second pigment into the sole mould, controlling the casting temperature to be 95 ℃, the casting pressure to be 0.3MPa, the casting speed to be 50mL/s and the feed liquid flow front speed to be 1.0mm/s, adopting step casting, firstly filling a cavity to be 1/3, stopping for 2s, and then refilling to be full, wherein the feed liquid flows along the cavity wall to avoid directly impacting the first pigment product;

(4) The method comprises the steps of heat preservation and vulcanization for 30min at 100 ℃, reducing the temperature to 80 ℃ at the later stage of vulcanization at the cooling rate of 2 ℃ per min, ensuring that a soft phase matrix is fully crosslinked, and firmly combining a hard sheet layer with the matrix, wherein isocyanate groups in a main body GCU material and surface active groups of a first color material product form chemical bonding through KH-560 in the reaction process, the hard sheet layer is directionally arranged to form a layered structure, the interlayer spacing is 5-10 mu m, and the isolated color paste coating prevents pigment molecules from diffusing to realize double color channeling prevention of chemical bonding and physical isolation;

(5) Firstly cooling to 60 ℃ at the speed of 3 ℃ per min, then cooling to 50 ℃ at the speed of 2 ℃ per min, demoulding, wherein negative pressure adsorption (adsorption force of 3N) is adopted to avoid scratching the surface during demoulding;

(6) After demolding, the sole was placed in a constant temperature and humidity environment at 23 ℃ and 50% RH for 24 hours to stabilize the shell-like layered structure, and the obtained product was shown in FIG. 2.

4. Post-treatment

1. The trimming, namely removing the overflowed material at the edge of the sole by adopting an automatic trimming machine, wherein the trimming precision is +/-0.1 mm, and the surface has no processing trace;

2. Cleaning, namely wiping the surface of the sole by absolute ethyl alcohol to remove residual release agent, and naturally air-drying in an explosion-proof fume hood (the ventilation air speed is more than or equal to 0.5 m/s) after cleaning, so as to avoid high-temperature baking (less than or equal to 60 ℃), and strictly forbidding open flame approaching.

5. Quality inspection

1. Color detection, comprising:

(1) And (3) color difference testing, namely testing 5 points by using a CR-400 color difference meter to obtain an average value, wherein the qualification standard is that the delta E of the first color material product is less than or equal to 0.7, and the delta E of the sole main body is less than or equal to 1.0.

(2) And verifying no color shifting, namely soaking the materials for 24 hours by using hot water at 60 ℃ and then aging the materials for 48 hours at 70 ℃, wherein the qualification standard is no color migration, and the double-color boundary is clear.

2. Performance testing, comprising:

(1) Interface binding force, referring to GB/T15256-2014, the qualified standard is that the peeling strength is more than or equal to 3.0MPa (no layering).

(2) The wear resistance is that the Taber abrasion is less than or equal to 11mg/1000 revolutions with reference to GB/T3903.2-2017.

(3) Impact resistance, referring to GB/T1843-2008, the qualified standard is that the impact strength of the simply supported beam is more than or equal to 23kJ/m < 2 >.

(4) Characterization of layered structure, SEM observation (magnification of 50 times), qualification criteria are 5-10 μm interlayer spacing, no agglomeration/delamination.

The second embodiment is different from the first embodiment in that:

in the raw material preparation step, a first color material comprises 100 parts of high-gloss CPU, 2 parts of isolated color paste and 0.3 part of anti-yellowing agent;

The second pigment comprises 100 parts of PTMG, 25 parts of MDI, 10 parts of BDO, 8 parts of mica sheets, 8 parts of nano alumina, 2.5 parts of inorganic color paste, 0.5 part of silane coupling agent KH-560, 0.2 part of dispersing agent, 0.1 part of antioxidant and 1.5 parts of toughening agent.

In the preparation step of the first pigment, the control parameters are that the temperature is 75 ℃, the rotating speed is 150rpm, and the stirring is carried out for 20min.

In the preparation of the second pigment, PTMG, MDI, BDO is weighed according to a proportion, mixed for 25min in a 60 ℃ vacuum stirrer, mica sheets and nano alumina are mixed and dried for 3h at 110 ℃, the temperature of a melting section of an extruder is controlled to be 190 ℃, the extrusion temperature is controlled to be 172 ℃ in a feeding section, 190 ℃ in a melting section and 197 ℃ in a head section, the rotating speed of a screw is 250rpm, and the second pigment particles are dried for 4.5h at 100 ℃.

In the first color material injection molding step, the mold is preheated to 55 ℃, the injection temperature is controlled to be 90-95 ℃, the injection pressure is controlled to be 48MPa, the injection speed is 25mm/s, the holding pressure is controlled to be 35MPa, the holding time is 12s, the mold is cooled to be 38 ℃, the mold is removed, and the control parameters of a plasma processor are that the power is 480W and the processing time is 35s.

In the injection molding step of the second pigment, the sole mold is preheated to 80 ℃, the casting temperature is controlled to 92 ℃ and the casting pressure is controlled to 0.4MPa when the second pigment is injected into the sole mold, the casting speed is 60mL/s, the temperature is kept at 95 ℃ for 35min, the temperature is reduced to 77 ℃ at the cooling rate of 3 ℃ per min in the later stage of vulcanization, the temperature is firstly reduced to 58 ℃ at the cooling rate of 3 ℃ per min, then the temperature is reduced to 48 ℃ at the cooling rate of 2 ℃ per min, the sole is demolded, and the demolded sole is placed in a constant temperature and humidity environment of 20 ℃ and 45% RH for 30h.

Other embodiments are the same as the first embodiment.

Embodiment III the present embodiment differs from embodiment one in that:

in the raw material preparation step, a first color material comprises 100 parts of high-gloss CPU, 4 parts of isolated color paste and 0.2 part of anti-yellowing agent;

100 parts of PTMG, 30 parts of MDI, 5 parts of BDO, 12 parts of mica sheets, 4 parts of nano aluminum oxide, 4 parts of inorganic color paste, 1 part of silane coupling agent KH-560, 0.8 part of dispersing agent, 0.5 part of antioxidant and 3 parts of toughening agent.

In the preparation step of the first pigment, the control parameters are that the temperature is 85 ℃, the rotating speed is 250rpm, and the stirring is carried out for 10min.

In the preparation of the second pigment, PTMG, MDI, BDO is weighed according to a proportion, mixed in a vacuum stirrer at 80 ℃ for 15min, mica sheets and nano alumina are mixed and dried at 130 ℃ for 1h, the temperature of a melting section of an extruder is controlled to be 200 ℃, the extrusion temperature is controlled to be 178 ℃ in a feeding section, 200 ℃ in a melting section and 203 ℃ in a head section, the rotating speed of a screw is 350rpm, and the second pigment particles are dried at 110 ℃ for 3.5h.

In the first color material injection molding step, the mold is preheated to 65 ℃, the injection temperature is controlled to be 90-95 ℃, the injection pressure is controlled to be 55MPa, the injection speed is 35mm/s, the holding pressure is 45MPa, the holding time is 8s, the mold is cooled to 42 ℃, the mold is removed, and the control parameters of a plasma processor are that the power is 520W and the processing time is 25s.

In the injection molding step of the second pigment, the sole mold is preheated to 90 ℃, the casting temperature is controlled to 98 ℃ when the second pigment is injected into the sole mold, the casting pressure is 0.2MPa, the casting speed is 40mL/s, the mold is preserved and vulcanized for 25min at 105 ℃, the cooling rate of 3 ℃ per min is reduced to 83 ℃ in the later stage of vulcanization, the mold is cooled to 62 ℃ at the rate of 3 ℃ per min first, then cooled to 52 ℃ at the rate of 2 ℃ per min, the mold is removed, and the sole is placed in a constant temperature and humidity environment of 25 ℃ and 55% RH for 20h after the mold removal.

Other embodiments are the same as the first embodiment.

Fourth embodiment the present embodiment differs from the first embodiment in that:

In this embodiment, in the first color injection molding step, the first color product is produced with a thickness margin. The bottom is equipped with the sunken recess that is adapted to first color material product in the sole mould, and its degree of depth just equals the thickness surplus of first color material product. When the first color material product is placed in the sole mould, accurate positioning can be achieved by placing the first color material product in the groove. After the second pigment is injection molded, the thickness allowance part of the first pigment product is cut off, namely, the part of the first pigment product protruding out of the sole is cut off, so that the first pigment product in the manufactured sole is completely embedded into the surface of the sole.

Other embodiments are the same as the first embodiment.

The first comparative example differs from the first example in that:

The isolated color paste (polyurethane coated organic violet pigment) in the first pigment is replaced by common organic violet paste (without polyurethane coating).

Other embodiments are the same as the first embodiment.

The second comparative example differs from the first example in that:

the first color product was not plasma treated.

Other embodiments are the same as the first embodiment.

The third comparative example is different from the first example in that:

the second coloring material is not added with a silane coupling agent.

Other embodiments are the same as the first embodiment.

The fourth comparative example differs from the first example in that:

the second pigment has no composite hard sheet layer, i.e. no mica sheet and no nano alumina.

Other embodiments are the same as the first embodiment.

The fifth comparative example is different from the first example in that:

The second pigment adopts one-time casting, the step casting is canceled,

Other embodiments are the same as the first embodiment.

The sixth comparative example is different from the first example in that:

And in the second pigment injection molding step, the constant temperature and humidity standing treatment is not carried out after demolding.

Other embodiments are the same as the first embodiment.

The seventh comparative example is different from the first example in that:

The first colorant is free of added anti-yellowing agents.

Other embodiments are the same as the first embodiment.

Comparative example eight differs from example one in that:

The single GCU material is used for dual-color glue-free connection, the main raw materials of the first pigment and the second pigment are GCU, the inorganic color paste is different, and the connection is realized through melting of a hot melt partition plate (TPU film), so that plasma treatment and a silane coupling agent are avoided.

Other embodiments are the same as the first embodiment.

Comparative tests were performed on the products of examples one to four and comparative examples one to eight above:

1. Color difference (delta E)

And adopting a CR-400 color difference meter to randomly select 5 test points (2 first pigment areas and 3 second pigment areas) of the sole, and taking an average value.

2. Color shifting property

Soaking the raw materials in 60 ℃ deionized water for 24 hours, drying, aging in a 70 ℃ aging box for 48 hours, and observing whether the color of the double-color boundary migrates or not.

3. Interfacial peel strength (MPa)

180℃Peel test was performed, the tensile speed was 50mm/min, the average value was taken for 3 groups, and reference was made to GB/T15256-2014.

4. Taber abrasion loss (mg/1000 revolutions)

The abrasion loss was calculated by weighing with a Taber abrasion machine, 1000g load, 1000 revolutions, and reference GB/T3903.2-2017.

5. Impact strength of simply supported beam (kJ/m 2)

The spline size was 80mm x 10mm x 4mm (taken from the stressed core area of the sole), no gaps, the average value of test 3 groups, reference GB/T1843-2008.

6. Integrity of layered structure (%)

SEM was magnified 50 times the observation cross section and the proportion of samples with 5-10 μm interlayer spacing and no agglomeration/exfoliation was counted.

7. Yellowing resistance index (delta YI)

After the xenon arc lamp is aged for 100 hours, the xenon arc lamp is tested by a CR-400 color difference meter, and the reference GB/T16422.2-2014 is made.

8. Product bubble Rate (%)

100 Pieces of air bubbles with the diameter more than or equal to 0.1mm are randomly extracted, and the reject ratio is calculated by an X-ray flaw detector, and QB/T2882-2013 is referred.

9. Dimensional accuracy (mm)

And testing the length, the width and the thickness of the three-coordinate measuring instrument, taking an average value for 5 times, and calculating deviation from a design value.

10. Surface Gloss (GU)

The 60 ° angular gloss meter tests the first color zone.

The test data are shown in tables 1-1 and 1-2.

Table 1-1 examples and comparative examples test data table 1

Sample numbering	Color difference (delta E)	Channeling condition	Peel strength (MPa)	Taber abrasion loss (mg)	Impact Strength (kJ/m 2)
						Example 1	0.5/0.8	Without any means for	3.2	10.0	24.0
Example two	0.6/0.9	Without any means for	3.0	11.0	23.0
						Example III	0.4/0.7	Without any means for	3.3	9.5	25.0
Example IV	0.5/0.8	Without any means for	3.4	9.8	24.5
						Comparative example one	1.8/2.2	Obvious migration	3.1	10.2	23.8
Comparative example two	0.5/0.8	Without any means for	2.0	10.1	20.0
						Comparative example three	0.5/0.8	Without any means for	2.2	10.3	21.0
Comparative example four	0.5/0.8	Without any means for	3.2	18.0	18.0
						Comparative example five	0.6/0.9	Without any means for	2.8	10.5	22.5
Comparative example six	0.5/0.8	Without any means for	2.9	13.0	21.0
						Comparative example seven	0.5/0.8	Without any means for	3.2	10.0	24.2
Comparative example eight	1.0/1.2	Slight	1.6	12.5	17.5

Tables 1-2 examples and comparative examples test data table two

Sample numbering	Lamellar integrity (%)	Yellowing resistance index	Bubble ratio (%)	Dimensional accuracy (+ -mm)	Glossiness (GU)
						Example 1	99.8	1.2	0.5	0.03	90.0
Example two	99.5	1.3	0.8	0.03	88.5
						Example III	99.9	1.1	0.4	0.03	91.2
Example IV	99.9	1.2	0.3	0.02	90.5
						Comparative example one	99.7	1.5	0.6	0.03	89.8
Comparative example two	99.6	1.2	0.7	0.03	80.2
						Comparative example three	99.7	1.3	0.5	0.03	89.5
Comparative example four	0.0	1.2	0.6	0.04	90.1
						Comparative example five	99.5	1.3	8.0	0.04	88.8
Comparative example six	99.8	1.2	0.7	0.05	89.2
						Comparative example seven	99.4	5.8	0.5	0.03	89.7
Comparative example eight	90.0	1.4	5.0	0.05	75.0

As can be seen from tables 1-1 and 1-2:

(1) In the first comparative example, the common non-coated color paste was used, the double color boundary showed obvious color migration, the color difference delta E was increased from 0.5 to 1.8 for the first colorant and from 0.8 to 2.2 for the second colorant, and the isolated color pastes used in the first to fourth examples were all free from color channeling. The reason is that the polyurethane coating can physically lock pigment molecules, can block diffusion even at the high temperature of 95-105 ℃, and solves the problem that the prior art cannot prevent and control molecular scale color channeling pain points through physical isolation from the source. If the color paste is replaced by the common color paste, the fineness of the double-color appearance is obviously reduced, and the requirements of the high-end sport shoes on the definition of the boundary cannot be met.

(2) The comparative example II was not subjected to plasma treatment, the interfacial peel strength was reduced from 3.2MPa of example I to 2.0MPa, the simply supported beam impact strength was reduced from 24.0kJ/m ² to 20.0kJ/m ², and the surface gloss was also reduced from 90.0GU to 80.2GU. The data show that the plasma treatment can promote the surface active groups of the CPU, and the surface roughness Ra=0.8-1.2 mu m can obviously enhance the physical occlusion effect with GCU. Without this treatment, the bicolor interface is prone to delamination under high intensity motion and cannot meet the dynamic stress requirements.

(3) In the third comparative example, no silane coupling agent was added, the interfacial peel strength was reduced from 3.2MPa to 2.2MPa, and the impact strength was reduced from 24.0kJ/m ² to 21.0kJ/m ². The epoxy group of the silane coupling agent reacts with-OH on the surface of the CPU, and the siloxane group is crosslinked with-NCO of the GCU to form a double bonding mechanism of physical occlusion and chemical bonding, so that the limitation of a single bonding mode in the prior art is broken through. If the reagent is not used, the interface bonding only depends on physical action, and the peeling strength cannot reach the high-end standard of more than or equal to 3.0 MPa.

(4) Comparative example four was not added with a hard sheet, the Taber abrasion amount increased from 10.0mg to 18.0mg, the simply supported beam impact strength decreased from 24.0kJ/m ² to 18.0kJ/m ², and no layered structure. The composite sheet layer and the GCU elastomer matrix form a shell-like layered structure, friction impact is resisted hard, and motion energy is absorbed by a soft phase, so that the industrial paradox that abrasion resistance is improved and shock absorption is needed to be reduced is broken. Without the structure, the wear resistance of the sole is greatly reduced, and the long-term use requirement of the sports shoes cannot be met.

(5) The fifth comparative example adopts one casting, the bubble rate of the product is increased from 0.5% to 8.0%, and the interfacial peel strength is reduced from 3.2MPa to 2.8MPa. The step-by-step pouring can avoid the feed liquid from directly impacting the CPU preformed piece, reduce the interface bubble residue and ensure the interface bonding uniformity. In the prior art, the defective rate is easily increased due to bubbles by adopting one-time filling, so that the process characteristic is important to mass production economy.

(6) Comparative example six was not subjected to constant temperature and humidity standing, the integrity of the layered structure was reduced from 99.8% to 85.0%, the Taber abrasion amount was increased from 10.0mg to 13.0mg, and the dimensional accuracy was deteriorated from.+ -. 0.03mm to.+ -. 0.05mm. The GCU matrix can be fully crosslinked in the standing process, the hard sheet layer is stable in position, and the loosening or deformation of the layered structure is avoided. If the step is not performed, the product performance fluctuation is large, and the qualification rate is reduced.

(7) The comparative example seven is not added with anti-yellowing agent, and the anti-yellowing index is increased from 1.2 to 5.8, and the delta YI of the far-ultra-high end product is less than or equal to 2.0. The first color material adopts a high-gloss CPU, is easy to be affected by ultraviolet rays to yellow, and the yellowing-resistant agent can effectively delay the process and ensure the long-term appearance texture of the product. If the component is not contained, the product is easy to yellow and age after being used, and cannot meet the high-end market demand.

(8) The comparative example eight does not use isolated color paste, and trace carriers may remain after the TPU film is melted, so that pigment molecules are slightly diffused, chromatic aberration is higher than that of the first embodiment, and slight migration occurs at the double-color boundary, thus proving the core advantage of the invention over physical isolation of the TPU film. The comparative example eight is free of plasma treatment and silane coupling agent, and only relies on physical bonding of hot melting of TPU film, the peeling strength is suddenly reduced from 3.2MPa to 1.6MPa, which is far lower than the requirement that the high-end sneaker is more than or equal to 3.0MPa, and the defect of weak bonding of the existing adhesive-free connecting interface is directly exposed. The Taber abrasion of the comparative example eight is increased from 10.0mg to 12.5mg, the TPU film melting residue possibly damages the directional arrangement of the hard sheet layers, the abrasion-resistant synergistic effect of the shell-like structure is weakened, the impact strength of the simply supported beam is reduced from 24.0kJ/m ² to 17.5kJ/m ², the impact load cannot be effectively transmitted due to weak interface bonding, stress concentration is easily generated at the interface, and the impact resistance is obviously reduced. The bubble rate of the comparative example eight is increased from 0.5% to 5.0%, trace gas is easy to generate in the hot melting process of the TPU film, the surface wettability without plasma treatment is poor, the gas is difficult to discharge, the dimensional accuracy is deteriorated from +/-0.03 mm to +/-0.05 mm, positioning deviation is caused by fluctuation of the TPU film thickness, the interface is uneven in thermal shrinkage, and the dimensional error is further amplified. The first pigment in the comparative example eight is changed from a high-gloss CPU to a GCU material, and the residual TPU film influences the surface flatness, so that the glossiness is reduced from 90.0GU to 75.0GU, and the requirements of high-end products on appearance texture cannot be met.

In conclusion, the core technical characteristics of the isolated color paste, the plasma treatment, the silane coupling agent, the composite hard sheet layer, the step pouring, the constant temperature and humidity standing, the anti-yellowing agent and the like are realized through chemical modification, structural bionic and process precise control, and the core pain points of industries such as unstable color channeling, interface combination, contradiction between wear resistance and shock absorption, insufficient dimensional accuracy and the like are solved. Any characteristic missing or replacement can lead to the obvious reduction of the performance of the product, and the comprehensive requirements of the high-end sports shoes on high interface binding force, accurate double-color effect, excellent functional performance and appearance texture cannot be met.

While the invention has been described above with reference to the accompanying drawings, it will be apparent that the invention is not limited to the embodiments described above, but is intended to be within the scope of the invention, as long as such insubstantial modifications are made by the method concepts and technical solutions of the invention, or the concepts and technical solutions of the invention are applied directly to other occasions without any modifications.

Claims

1. A double-color molding process for shoemaking is characterized by comprising the following steps:

S1, respectively preparing a first pigment and a second pigment,

The first color material comprises the following raw materials, by weight, 100 parts of a pouring polyurethane elastomer, 2-4 parts of an isolated color paste and 0.2-0.3 part of an anti-yellowing agent;

The second pigment comprises the following raw materials, by weight, 100 parts of polytetrahydrofuran glycol, 25-30 parts of diphenylmethane diisocyanate, 5-10 parts of 1, 4-butanediol, 8-12 parts of mica sheets, 4-8 parts of nano alumina, 2.5-4 parts of inorganic color paste, 0.5-1 part of silane coupling agent, 0.2-0.8 part of dispersing agent, 0.1-0.5 part of antioxidant and 1.5-3 parts of toughening agent;

S2, injection molding the first color material, and performing plasma treatment;

S3, placing the first pigment product subjected to plasma treatment into a sole mould, and accurately positioning, then injecting the second pigment into the sole mould, carrying out heat preservation and vulcanization treatment, cooling, demoulding, and forming the bicolor sole;

2. The two-color molding process for shoemaking according to claim 1, wherein the preparation of the first coloring material in step S1 comprises the steps of:

3. The two-color molding process for shoemaking according to claim 1, wherein the preparation of the second coloring material in step S1 comprises the steps of:

4. The two-color molding process for shoemaking according to claim 1, wherein the specific steps of step S2 are as follows:

5. The two-color molding process for shoemaking according to claim 1, wherein in step S3, the sole mold is preheated to 80-90 ℃ and then the first color material product after plasma treatment is put in;

And/or the positioning precision of the accurate positioning is +/-0.02 mm.

6. The two-color molding process for shoemaking according to claim 1, wherein in step S3, the casting temperature is controlled to be 95+ -3deg.C, the casting pressure is controlled to be 0.2-0.4MPa, and the casting speed is controlled to be 40-60mL/S when the second pigment is injected into the sole mold;

7. The two-color molding process for shoemaking according to claim 1, wherein in the step S3, the heat-preserving vulcanization is carried out for 25-35min at 95-105 ℃ and the temperature is reduced to 80+ -3 ℃ at 2-3 ℃ in the later stage of vulcanization;

and/or the cooling is to cool to 60+/-2 ℃ at a rate of 3 ℃ per minute and then cool to 50+/-2 ℃ at a rate of 2 ℃ per minute.

8. The two-color molding process for shoemaking according to claim 1, wherein in step S3, after demolding, the sole is left to stand in a constant temperature and humidity environment of 20-25 ℃ and 45% -55% RH for 20-30 hours to stabilize the shell-like layered structure.

9. The dual-color molding process for shoemaking according to claim 1, wherein in the step S4, the trimming is performed by removing the flash at the edge of the sole with a trimming precision of + -0.1 mm, and the trimming direction is consistent with the layered arrangement direction during trimming, thereby avoiding damaging the layered structure of the main body.

10. The two-color molding process for shoemaking according to claim 1, wherein in step S4, the surface of the sole is cleaned by wiping with absolute ethyl alcohol to remove the residual release agent, and naturally air-dried after cleaning.