US 9,617,395 B2  6  5  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.  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  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.  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.  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.  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.  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 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.  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.  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.  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).  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.  where "n" represents the number of measurements (30).  n  ~  ( short diameter/ long diameter)  [1]  sphericity  = ;~i  x 100  n 