The Difference Between Polyether TPU and Polyester TPU (Part 1) - Guangyuan Ruifeng New Materials

Category: TPU (popular science, no product)

Release Time: 2020-08-03

Summary: TPU's soft segments can use a variety of polyols, which can be roughly divided into polyether and polyester types. Polyether type: high strength, hydrolysis resistance and high resilience, good low-temperature performance. Polyester type: better tensile properties, flexural properties, abrasion resistance, solvent resistance and higher temperature resistance.

TPU's soft segments can use a variety of polyols, which can be broadly classified into polyether and polyester types. Polyether type: high strength, hydrolysis resistance, and high resilience, good low-temperature performance. Polyester type: better tensile properties, flexural properties, abrasion resistance, solvent resistance, and higher temperature resistance. (TPU crosslinking agent manufacturer)

1. Differences in raw materials and formulations

(1) The main raw materials for polyether-type TPU include 4,4'-diphenylmethane diisocyanate (MDI), polytetramethylene ether glycol (PTMEG), and 1,4-butanediol (BDO). The amount of MDI is about 40%, PTMEG accounts for about 40%, and BDO accounts for about 20%. (TPU crosslinking agent manufacturer)

(2) The main raw materials for polyester-type TPU include 4,4'-diphenylmethane diisocyanate (MDI), 1,4-butanediol (BDO), and adipic acid (AA). The amount of MDI is about 40%, AA accounts for about 35%, and BDO accounts for about 25%. (TPU crosslinking agent manufacturer)

2. Molecular weight distribution and its influence

The relative molecular weight distribution of polyethers follows the Poisson probability equation, with a relatively narrow molecular weight distribution; while the relative molecular weight distribution of polyester diols follows the Flory probability distribution, with a relatively wide molecular weight distribution. (TPU crosslinking agent manufacturer)

The molecular weight of the soft segment affects the mechanical properties of polyurethane. Generally speaking, assuming the same polyurethane molecular weight, if the soft segment is polyester, the strength of the polyurethane increases with the increase of the polyester diol molecular weight; if the soft segment is polyether, the strength of the polyurethane decreases with the increase of the polyether diol molecular weight, but the elongation increases. This is because the polyester soft segment itself has stronger polarity, and a larger molecular weight means higher structural regularity, which is beneficial to improving strength, while the polyether soft segment has weaker polarity. If the molecular weight increases, the relative content of hard segments in the polyurethane decreases, and the strength decreases. (TPU crosslinking agent manufacturer)

3. Comparison of mechanical properties

The soft segments are composed of polyether, polyester, and other oligomeric polyols. The soft segment accounts for the majority of polyurethane, and the properties of polyurethane prepared from different oligomeric polyols and diisocyanates vary. Polyurethane elastomers and foams with stronger polarity polyesters as soft segments have better mechanical properties. This is because polyurethane made from polyester contains a large number of polar ester groups. In this polyurethane, not only can hydrogen bonds form between hard segments, but polar groups on the soft segments can also partially form hydrogen bonds with polar groups on the hard segments, allowing the hard phase to be more uniformly distributed in the soft phase, acting as elastic crosslinking points. At room temperature, some polyesters can form soft segment crystals, affecting the performance of polyurethane. The strength, oil resistance, and thermal oxidation stability of polyester polyurethane are higher than those of PPG polyether type, but the hydrolysis resistance is lower than that of polyether type. (TPU crosslinking agent manufacturer)

4. Comparison of hydrolysis stability

After being protected with carbodiimide, the hydrolysis resistance of polyester thermoplastic polyurethane is improved. Polyetherester thermoplastic polyurethane and polyether thermoplastic polyurethane have the best hydrolysis resistance at high temperatures. (TPU crosslinking agent manufacturer)

Polyesters are easily attacked by water molecules and break down, and the acid generated by hydrolysis can catalyze the further hydrolysis of the polyester. The type of polyester has a certain influence on the physical properties and water resistance of the elastomer. With the increase of the number of methylene groups in the polyester diol raw material, the water resistance of the obtained polyester polyurethane elastomer is improved. The lower the ester group content, the better the water resistance. Similarly, the water resistance of polyurethane elastomers synthesized using long-chain dibasic acids is better than that of polyurethane elastomers synthesized using short-chain dibasic acids. (TPU crosslinking agent manufacturer)

5. Comparison of microbial resistance

Polyester soft thermoplastic polyurethane will be eroded by microorganisms after long-term contact with moist soil, while polyether soft or hard thermoplastic polyurethane and polyether thermoplastic polyurethane or hard thermoplastic polyurethane are usually not eroded by microorganisms. (TPU crosslinking agent manufacturer)

6. Price comparison

Polyether polyurethane elastomers are much more expensive than polyester polyurethane elastomers, mainly because:

① Polyether polyurethane elastomers have good hydrolysis resistance, low-temperature resistance, and bending resistance.

② Compared with polyester polyols, the raw materials for polyether polyols that constitute the TPU soft segment are more expensive.

③ The production process of polyether polyols is much more complex than that of polyester polyols.

④ The various process conditions are more difficult to control during the production of polyether polyols.

⑤ In the production of polyether polyols, higher requirements are placed on the production equipment, and certain protective measures must be taken during the production process.

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

Keywords: The Difference Between Polyether TPU and Polyester TPU (Part 1) - Guangyuan Ruifeng New Materials

Related Solutions

Previous: TPU Injection Molding Process - Guangyuan Ruifeng New Materials

Next: Differences between polyether TPU and polyester TPU (Part 2) - Guangyuan Ruifeng New Materials

Guangan///Guangyuan,Guoyuan///Guangyuan,Ganguan///Guangyuan

Sorry，当前栏目暂无内容!

您可以查看其他栏目或返回 首页

Sorry，The current column has no content!

You can view other columns or return Home