Poly(1-Butene) Resin Composition for Strength-Moldability Balance
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Solution Overview
Problem
Poly(1-butene) resin compositions for water and hot water supply pipes face challenges in achieving a balance between strength and moldability due to low hardening rates and dimensional accuracy issues, particularly when using nucleating agents like EBSA and titanium oxide, which shorten the half-crystallization time and compromise pressure-resistance strength.
Innovation Solution
A poly(1-butene) resin composition with specific formulation, including a poly(1-butene) resin and an ethylene-based polymer produced using a metallocene catalyst, with controlled molecular weights and densities, and a specific content ratio to achieve a longer half-crystallization time and improved moldability, ensuring excellent balance between strength and moldability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If EBSA is used as a nucleating agent to ensure pressure-resistance strength, then half-crystallization time is shortened, but dimensional accuracy is lowered
Solution Approach 1:
The patent employs polyethylene wax as a short-living nucleating agent that performs its function during the critical crystallization phase and then gradually integrates into the matrix structure. This approach provides the necessary nucleation effect for pressure resistance during molding while the controlled degradation and integration minimize long-term dimensional instability, effectively resolving the contradiction between achieving pressure strength and maintaining dimensional accuracy
2Ease of manufacture
If titanium oxide is combined with EBSA to achieve color properties, then light blocking is improved, but half-crystallization time is further shortened, causing further lowering of dimensional accuracy
Solution Approach 1:
The patent extracts and separates the nucleating function from the coloring function, using polyethylene wax as the primary nucleating agent instead of relying on the nucleating side-effect of titanium oxide combined with EBSA. This separation allows titanium oxide to focus on its primary function of light blocking and color provision without the harmful side-effect of excessive nucleation that shortens half-crystallization time and compromises dimensional accuracy
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The composition provides a poly(1-butene) resin with a long half-crystallization time, enabling the formation of molded bodies with enhanced strength and moldability, while minimizing the use of low-molecular weight components to prevent creep rupture, thus optimizing pipe performance.
Implementation Method 1
a poly (1-butene) resin (A) having a melt flow rate of 0.01 to 50 g/10 min... an ethylene-based polymer (B)... capable of ensuring pressure-resistance strength at high temperatures... long half-crystallization time
Implementation Method 2
an ethylene-based polymer (B) produced using a metallocene catalyst
Data Source
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AI summary
A poly(1-butene) resin composition having a long half-crystallization time and being able to favorably form a molded body having an excellent balance between strength and moldability, and a molded body are provided. The poly (1-butene) resin composition of the present invention contains a poly (1-butene) resin (A) having MFR (JIS K 6721, 190°C, 2.16 kg) of 0.01 to 50 g/10 min and an ethylene-based polymer (B) satisfying the requirements (i) to (iii), and satisfies the requirements (I) and (II): (i) a mass-average molecular weight as measured by GPC is in the range of 3000 to 9000 in terms of polyethylene; (ii) a ratio (Mw/Mn) of a mass-average molecular weight as measured by GPC to a number-average molecular weight as measured by GPC is in the range of 1.0 to 3.5; (iii) a density d (JIS K 7112, density gradient tube method) is in the range of 890 to 980 kg/m3; (I) a content (% by mass) [WA] of the poly (1-butene) resin (A) is 95.000 to 99.999, and a content (% by mass) [WB] of the ethylene-based polymer (B) is 0.001 to 5.000 (with the proviso that the total of WA and WB is 100% by mass) ; and (II) a half-crystallization time T1/2 (second(s)) of the resin composition at an isothermal crystallization temperature 90°C, as determined by DSC measurement, a density d (kg/m3) of the polymer (B), and a content (% by mass) [WB] of the polymer (B) satisfy a relationship of T1/2>(0.27×WB-1.34)×d-274×WB+1389.