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raw material, further, solid phase polymerization using low› molecular polyamide 1010 as a raw material and the like. 

Although decanediamine and sebacic acid, which are raw materials, can be obtained by chemical conversion from a raw material originating from petroleum or a raw material originating from biomass, it is not particularly restricted in the present invention, and it is preferred to employ a raw material originating from biomass from the viewpoint of global environmental protection. 

Although the degree of polymerization of polyamide 1010 resin is not particularly restricted, from the viewpoint of stiffness of polymer particles to be obtained, as the weight average molecular weight, the lower limit thereof is 1,000 or more, preferably 5,000 or more, more preferably 10,000 or more, further preferably 12,000 or more, and particularly preferably 15,000 or more. Further, the upper limit thereof is 1,000,000 or less, preferably 500,000 or less, more preferably 100,000 or less, further preferably 50,000 or less, and particularly preferably 30,000 or less. Where, the weight average molecular weight is defined as a value converted in terms of polymethacrylic methyl from a value which is determined by gel permeation chromatography (GPC) using hexafluoroisopropanol as a solvent. 

The average particle diameter of polyamide 1010 polymer particles 1 µm to 100 µm, and the upper limit is preferably 80 µm or less, more preferably 60 µm or less, further preferably 50 µm or less, and particularly preferably 30 µm or less. Further, the lower limit is 1.0 µm or more, preferably more than 1.0 µm, more preferably 5 µm or more, further preferably more than 5 µm, particularly preferably 10 µm or more, and extremely preferably more than 10 µm. 

The average particle diameter of polyamide 1010 polymer particles is defined as a diameter determined by specifying diameters of 100 particles randomly selected from a photo› graph taken by a scamiing electron microscope and calcu› lating the arithmetic average. In the photograph, in case where a particle is not a perfect circle, namely, in such a case where the particle has an ellipse-like shape, the maximum diameter of the particle is employed as its particle diameter. To precisely measure the particle diameter, the measurement of the particle diameter is carried out after enlarging the photograph at a magnification of at least 500 times or more, preferably 1,000 times or more. 

Further, in polyamide 1010 polymer particles, it is pre› ferred that the particle diameter distribution of the particles is narrow. The particle diameter distribution can be expressed by a particle diameter distribution index in equa- tion (2) described later. The particle diameter distribution index of polyamide 1010 polymer particles according to the present invention is 3 or less, preferably 2.5 or less, more preferably 2.0 or less, further preferably 1.8 or less, particu› larly preferably 1.5 or less, and extremely preferably 1.3 or less. Further, although a preferred lower limit thereof is not particularly restricted, theoretically the lower limit is 1 or more. 

The polyamide 1010 polymer particles are characterized in a point that the sphericity is high, and it is understood that they exhibit a good flowability because of high sphericity. 

Sphericity can be expressed as a value calculated by the following equation (1) after determining long diameters and short diameters of 30 particles randomly selected from a scanning electron microscope photograph, and the closer to 100 it is, the higher the sphericity is. 

<img src='content_image/946195.jpg'>

where "n" represents the number of measurements (30). 

The sphericity of polyamide 1010 polymer particles is 80 or higher, preferably 85 or higher, more preferably 90 or higher, further preferably 95 or higher. Although a preferred upper limit is 100 or lower, usually even if it is 90 or lower, a sufficient effect such as improvement of slidableness and smooth touch feeling can be achieved. If the sphericity is lower than 80, the sphere becomes close to an ellipse shape, and a smooth touch feeling camiot be obtained. 

Polyamide 1010 polymer particles are characterized in a point that the crystallinity is very high, and from this feature, they have a feature that the elasticity modulus of the polymer particles is high as compared with the conventional one. It is possible to determine the degree of the highness of the crystallinity by carrying out particle X-ray measurement, and the polyamide 1010 polymer particles have peaks at characteristic positions of 20 degrees and 24 degrees in a spectrum of diffraction angle 28 determined by wide angle X-ray scattering using a Ka ray of copper atom (Cu). 

In particular, the peak at a position of 24 degrees in a spectrum of diffraction angle 28 determined by wide angle X-ray scattering is a peculiar peak observed when the crystal structure of polyamide 1010 resin has developed, and the polyamide 1010 polymer particles have that peak. 

Further, in spite of the developed crystal structure, poly› amide 1010 polymer particles have characteristics being good in flowability and being small in repose angle of particles together because the sphericity is high as their shapes. 

The repose angle of particles formed from polyamide 1010 polymer particles is 30 degrees or less, preferably 25 degrees or less, more preferably 20 degrees or less, and further preferably 15 degrees or less. Although the lower limit of the repose angle is not particularly restricted, it is greater than 0 degree. 

Polyamide 1010 polymer particles are characterized in that, because the crystallinity is high, the mechanical strength is high and the elasticity modulus is high. 

The elasticity modulus of the polyamide 1010 polymer particles is 1.6 GPa or more, preferably 1.7 GPa or more, more preferably 1.8 GPa or more, further preferably 1.9 GPa or more, and particularly preferably 2.0 GPa or more. 

To determine the elasticity modulus of particle-like mate› rial, by using a micro compression testing machine supplied by Shimadzu Corporation and using Hertz’s theory of elas› ticity, the elasticity modulus can be calculated. 

Thus, by having a high elasticity modulus, since the application range to slidable members and the like is extended, they become material useful as polymer micropar› ticles. 

Polyamide 1010 polymer particles are characterized in a point that, because of the developed crystal structure, light reflection is caused as a reflection originating from the crystal structure in the particle in addition to a reflection at a particle interface, and therefore, in particular, an L value, which represents a lightness determined by spectrophotom› etry, becomes high. 

The L value representing the lightness is preferably 70 or higher, more preferably 80 or higher, and particularly pref› erably 85 or higher. If the L value is lower than 70, factor of coloring becomes great, and in case being employed in use 

