TPU Formulation Design and Application - Guangyuan Ruifeng New Materials

Category: TPU (popular science, no product)

Release Time: 2020-06-22

Summary: TPU formulation design is a rather complex process. After selecting the main raw materials based on the required performance, it is also necessary to consider the relevant parameters of the raw materials, such as: the purity of diisocyanate; the purity, acid value, hydroxyl value, and water content of the polymer polyol; the purity and water content of the chain extender, etc. Based on this, the R value and hard segment content (Ch) are determined, and finally the production formula is determined.

1. TPU Formulation Design

TPU formulation design is a rather complex process. After selecting the main raw materials based on the required performance, the relevant parameters of the raw materials must also be considered, such as: the purity of diisocyanate; the purity, acid value, hydroxyl value, and water content of the polymer polyol; the purity and water content of the chain extender, etc. Based on this, the R value and hard segment content (Ch) are determined, and finally the production formula is determined. (TPU crosslinking agent manufacturer)

(1) Determination of Basic Raw Material Parameters

The determination of basic raw material parameters plays a crucial role in TPU formulation design. Only after determining the basic parameters of the raw materials can the formula be calculated. The parameters of the raw materials that need to be determined during the formulation design process include: the molecular weight of the macromolecular diol, the purity of the diisocyanate and the small molecule chain extender, etc. Among them, the hydroxyl value of the macromolecular alcohol can be determined by the phthalic anhydride acylation method or acetylation method, and the acid value can be determined by the KOH titration method; the isocyanate purity can be determined by the di-n-butylamine addition-hydrochloric acid back titration method; the water content of the macromolecular alcohol and the small molecule chain extender can be titrated using Fischer reagent. (TPU crosslinking agent manufacturer) 1 mol of water consumes 1 mol of diisocyanate, so the water content in the chain extender and macromolecular alcohol must be strictly controlled, and the raw materials must be dehydrated in advance, with a required water content of about 0.03%-0.05%. Otherwise, it will have a significant impact on the results. (TPU crosslinking agent manufacturer)

The molecular weight of the macromolecular diol can be calculated using the following method: In the formula, 2---the functionality of the macromolecular alcohol, which can be changed according to the actual situation. (TPU crosslinking agent manufacturer)

(2) Determination of Basic TPU Parameters

After determining the basic parameters of the TPU raw materials, the most important thing is the -NCO/OH (R) value and hard segment content (Ch) of the basic TPU formula. The hard segment content refers to the mass percentage of the hard segment in the TPU, and is another important parameter in TPU formulation design. The hard segment content directly affects the hydrogen bonding, microphase separation, and crystallization performance of the TPU, and is the main factor determining its morphology. When the hard segment content is low and the mass is small (e.g., 10%), the hard segment is easily dissolved in the soft segment, and the TPU becomes a single soft segment phase; when the hard segment content is high but less than about 40%, the hard segment is dispersed on the soft segment, and the soft segment is the continuous phase; in these two cases, the TPU mainly exhibits the superior performance of the soft segment phase, such as good low-temperature performance, elongation, and elasticity, but the strength, modulus, abrasion resistance, and heat resistance are poor. (TPU crosslinking agent manufacturer) When the hard segment content is about 40-60%, the TPU microphase separation is good, and both the soft segment phase and the hard segment phase may be continuous phases. At this time, the TPU exhibits good comprehensive performance, with good elongation, elasticity, strength, modulus, abrasion resistance, and low-temperature performance. When the hard segment content is greater than 60%, the soft segment is dispersed in the hard segment, and the hard segment is the continuous phase. At this time, the TPU mainly exhibits the performance of the hard segment phase, with good mechanical strength, high modulus and abrasion resistance, and good heat resistance, but poor low-temperature performance, elongation, and elasticity. When designing the TPU formula, the corresponding hard segment content range should be determined according to the performance requirements of the product, a preliminary experimental formula should be calculated, and the required formula should be obtained through experiments and further adjustments of the experiments. (TPU crosslinking agent manufacturer)

In TPU, under normal circumstances, R is controlled between 0.95 and 1.05. Most are between 0.98 and 1.02. When R < 1, the TPU has a pure linear structure and is a thermoplastic product; when R > 1, in addition to producing linear TPU, there are also some branched or even cross-linked structures, which are semi-thermoplastic products. Pure linear TPU is meltable and soluble, and can be melt-processed such as extrusion, calendering, injection molding, blow molding, and can also be solution-processed such as making coatings, adhesives, pastes, etc. Semi-thermoplastic TPU is meltable but not completely soluble, and can only be melt-processed, not solution-processed. Therefore, when designing the formula, the appropriate R value should be selected according to the performance requirements of the product. ,<>sA:=ny (TPU crosslinking agent manufacturer)

Guoyuan Ruifeng New Materials Co., Ltd., a TPU crosslinking agent manufacturer, we have mature production processes and can definitely meet your needs.

Keywords: TPU Formulation Design and Application - Guangyuan Ruifeng New Materials

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